Depression/ignorance tortured and killed my relationship

This is going to be pretty long and probably depressing. I just want to get this off my chest and know if anyone has been through the same/how they dealt with it (tl;dr/my questions at the bottom):

My friends and I were making YouTube videos. We had a pretty big number of subscribers. I went away on holiday and returned to see our channel had some beautiful artwork on it. Naturally, I asked the guys about this. I was pulled into a conversation with the artist over the internet with my friend. He introduced me to her (thank God, I would never be able to do it myself). She had a beautiful voice. We threw around small talk. I went to sleep extremely happy. I knew I liked her.

The next day she drummed up conversation with me. I was so **** happy. We talked for about 10 hours about anything and everything. I just kept on falling for her. We moved to Skype eventually. She was beautiful. I knew I was extremely lucky, which made me think that there was no way she liked me, so I neglected to say. For 9 months. We kept talking for crazy long periods of time, even through an 8 hour time difference. That was the best conversation I have ever had. It was so enriching. She kept on dropping hints that she liked me but I missed all of them.

One day I tested my luck. I told her I liked her. Turns out she had felt the same as me since the first time we spoke. She was on the verge of giving up when I told her. It was the best day of my life. We kept talking. She started to draw pictures of us together. It was so unrealistically romantic I was sure I was in a film. She made me so happy. I was saving up for a plane ticket to go visit her. Everything was looking up. Then depression hit.

I do not know what happened. I became lost, scared, suicidal, everything. Our conversations always broke down to me and my depression. It was killing our relationship though I was blissfully unaware. I became paranoid that when she would go out she would be off with other guys. This continued for maybe 4 months. Then one day it all died.

I was still so in love with her. She tells me she had stopped loving me a while ago. She tells me how much she is hurting. She tells me she had cried herself to sleep most nights. And I finally realized what I had done. For the last 4 months I had been psychologically abusing her and making her life hell whilst I was entirely fixated on my own depression and was ignoring everything else. The guilt was (and still is) unbearable. I broke down. No amount of truthful apologies and sadness on my part could fix it.

We struck a deal. I would stop talking to her for a week (consider the 5 hours a day conversations this was killer) and I would change. She would see if she could trust me again in that time. The week was horrible. Every day hurt. I was cold and so alone. I realized what I had to be grateful for. I felt I genuinely changed. But it was too late. She had been talking to another guy for months and, in that week, she had fallen for him. I died.

Skip forward a year and a half. They are still together. I am still alone and still hurt, still miss everything, still remember every detail of her face and voice and everything. I think I still love her, but I don't know. I don't really know anything anymore. In the 1 and 1/2 years there were periods of ~4 months no talking. It hurt as much as it used to. Just recently I started speaking to her again. I send paragraphs, she sends single words. I'm stuck. The most beautiful thing I've ever known to exist is gone. It kills me every day. I don't know if I'm obsessed or I'm just still recovering. It ******* hurts.

Tl;dr: I was in a relationship. It was perfection, felt like I was in a film. Depression came along. It messed it up. She told me to come back when I changed. I changed. She had already moved on. This was a year and a half ago. I can't help but want to talk to her. She is still all I can think about. I still think she's amazing. She hardly talks to me when I speak to her lots. What do I do?

Questions:
Whether you read the long version or the tl;dr I appreciate it.
-Has anyone been in a similar situation to this where depression broke a relationship? I'm sure it can't just be me
-If yes, how did you deal with it? How did you move on?
-Is there anyway to make sure I won't do this kind of thing again?
-Is it normal to still hurt after this amount of time?
-Am I being unnecessarily negative and overreacting?

Any kind of input would be great because I've been stuck in this loop for a while now and I'd really love to get out.

Here's a picture of some art she made for us: http://puu.sh/6bemr.jpg
There is literally 50 more. She also made me audiobooks for when I was away. I lost something great.

Hey Kira, I'm so sorry to read about this. I am not in a position to answer your questions though as I've not gone through something similar. But I want you to know that I feel for you and I'm pretty sure that when you truly love someone, and something goes wrong between the two of you..it hurts like no words could ever describe. So you feeling like this, can't be any more normal.

Any way to make sure you won't do this again? Work out your issues. Be happy with yourself first, and be healthy mentally before you step into another relationship. Or history might just repeat itself, unless you are able to keep it under control.

She's an amazing artist. I'm sorry for what you had to go through though. Best of luck, don't give up. *hugs*

-Has anyone been in a similar situation to this where depression broke a relationship? I'm sure it can't just be me

Yes. My fiance and I were in a relationship for 5 years and she eventually left me. I was nasty toward her because of my emotional issues. Quick to anger, kept to myself, communicated very little with her etc. I wasn't being emotional abusive on purpose but that's what pretty much happen. She really did love me because she stayed and dealt with my attitude for so long so I give her credit for that.

-If yes, how did you deal with it? How did you move on?

Well, the first couple of months after were kinda a revelation. At first, you have to gut reaction of "I'll change! I'll change!" but slowly I began to ask myself what exactly am I changing? I can't really change my depression but I can change how I act toward people close to me. So that's what I did, but she was over it and moved on. Time helped me move on. Limited contact with her, changed my thought process so I didn't think of her all the time and eventually I got over it. Probably took me 5-6 months?

-Is there anyway to make sure I won't do this kind of thing again?

Learn from what happen. Recognize behavioral patterns that you had and force yourself to change directions. Before I would get pissed and bored when she told me her boring stories about work (Literally the same story everyday) and that would cause me to shut down, zone out, etc Now my current gf tells me boring ass stories about her friends or something I'm not interested in I pay attention, try to relate, try not to let it get to me. Long story short is that you have to learn from what you did wrong and not do it again and understand why.

-Is it normal to still hurt after this amount of time?

Personally, it seems a little long but everybody is different and they all take their own amount of time to heal.

-Am I being unnecessarily negative and overreacting?

No.

I've dealt with something similar, depression wise. It steals who you are. It puts a blinder over your eyes and every day seems to clash with the next. Work on YOU first so the next girl can get to know the REAL you.

I have no personal experience with things like that, I just want you to know that I feel for both of you, and I hope both of you will get to be happy someday. She may be a step ahead, but I still wish for both of you to be truly happy after what you went through.
No one is at fault I think. But that does not mean things can go back, and they shouldn't. I mean your behavior to be specific. If you realize what you did to her during that period, you should be conscious of that from now on, not to ever hurt anyone you love ever again like that.

After reading this, I was very much reminded of my own situation. It never blossomed into a proper relationship, but I think it could have, if I were a little more conscious of my thoughts and words. I think this happened to me too. I got to know this girl, and she used to say how I made her so happy and that she wanted me around. She would tease me a little bit too, and that was probably my opportunity to tease her back. But I didn't pick up on it until after the fact. Also, she would sometimes open up to me about her problems. At first, I was the one to cheer her up, I was the one that made her feel better. She would constantly try to talk to me whenever possible.

But then I let my guard down and started talking too much about my own problems, how I felt that I couldn't solve them for whatever reason - that I was too old, that I was a natural-born loser, fear, doubt, all that stuff. She would help me with things, but I think this is where I went wrong - I should have just kept cheering her up and trying to talk about interesting things, and actually done interesting things with my own life so that I'd have something to talk to her about, instead of talking about my problems. I wasn't actually DOING anything with my life, just all talk, no action. I was all mopey about everything. And I think that turned her away, plus the fact that I missed all my opportunities she gave me to tease her playfully/sexually.

The thing that sucks the most is how hard it is to turn it around. It really angers me how girls feel that rejection has to be so final. If I just fix the thing that was wrong, in my case my feeling like a loser, negativity/mopeyness, and actually do stuff with my life, then why can't I be the same person that made her feel good all those months???? Idk. I guess only time will tell but I refuse to give up. I've met maybe 2 other girls in my whole life that even come close in terms of beauty and fascination, and they are of course also taken. I moved too slowly, and now no one exciting is left. It sucks.