Dating your friend's ex?

I have a friend, let's just say her name is Victoria. Me and Victoria basically met this guy named Ryan long time ago. That time me and Victoria both had a crush on him but I didn't tell Victoria I did , but she told me that she liked him.
From that day I didn't really want to get involved with both of them. Then I found out they started to date. Didn't really care at first but I still supported them.
Most of the time I usually ask Victoria or Ryan how their love life is going and they tell me. Sometimes when they have problems with eachother's relationships, I help them solve it. So basically i'm just like a third wheel I guess?
I looked at Ryan as a friend that time and I never in my mind would flirt with him or anything.
So after 8 months of them being together , One day Ryan was on her Facebook (yeah they know eachother's ..)
Ryan caught her flirting with another guy and he showed me the conversation. I know it's wrong going into someone's business but I have completely lost all Respect for Victoria . How can she do that after all the time Ryan and her were together?
Ryan then tells me "she's just with me because she doesn't want to hurt me by breaking up with me. " blah blah blah etc..
A few months passed .. Ryan then says he's falling in love with me?
I was in complete shock. I told him to stop catching feelings and to stop right away but he said he couldn't.
At first I didn't want to date him because he's my friend's ex and I wouldn't want her to hate me or anything
But I can't help it anymore.. I'm falling in love with him and it feels right..

Though there is another problem.. Even if I were to date him. I keep getting insecure and saying to myself "Victoria and Ryan probably had been through more than me and him will ever go through"
it hurts..
Can anybody help me or tell me what to do and how to stop feeling insecure and thinking of the past because I always go back to it..

If he's in a relationship, 'falling in love' with you and suspects his girlfriend is too afraid to break up with him, why is he still IN that relationship? I think I'd be confronting her before discussing it with her friend.

I would be suspicious, because even if any of that IS true, he could be that type of guy who'll get together/sleep with you to get back at Victoria.

You might be falling for this guy but I'd listen to my brain first.

9006 is right. If he felt like Victoria was cheating on him and only stuck around because she didn't want to hurt him then he could and should have confronted her then ended the relationship himself. How did the relationship end anyways? I don't think you mentioned how they actually broke up. Either way I'd avoid him because anyone guy or gal who pursues another right after a relationship ended is likely either going use you as a rebound or revenge.

He may be saying the right things to you, but who's to say he didn't log into Victoria's account and 'flirt' with someone himself? The whole thing is quite suspicious.

The first thing that stands out to me is why is he not discussing his relationship problems (her flirting with another guy) with her first instead of someone outside the relationship?
If the relationship were irretrievably broken, a gentleman would end it before moving on to another partner. Something to think about.

-Teresa