Doing things for yourself

I won't bore you with details. In my early 20's a tragic event occured in my life where I lost everything, job, friends.... lets just say barring family I lost everything. I ended up in a very dark place for many a year, of course there were times of hope in there but nothing ever came of it. There were times I would not be able to leave the house and when I did would cross the street to avoid passing strangers. It was a long dark time but is long since over, I met someone.

At the time we were amazing for each other, lifted each other, made each other feel alive again. I lived for her, lived for us, wanted to give her what she deserved which was far more than I had. So I worked on that, I was dedicated to that, the self improvement... I went from from a decade of unemployment to pulling in £2.5k a month and thats just the things you can measure, not the mental, emotional things. The situation was always complicated and difficult but we always tried, we needed a lot of pateince to get to the place we wanted to be and I think it is my lack of patience, my stressing, my mental health issues and my one track mind, that it was this or nothing is why it is now over. 

I had all my eggs in one basket, I lived for us and not for me, I did things always with us in mind and not me. It has been almost 2 decades now since I have lived for me, wanted to better me, wanted me to be happy soley for me. How do I go about doing it. How do I push myself, better myself, do things for me that will make me happy.

I would suggest finding a hobby. Something YOU like to do. Find a meetup group or even just do it alone. Something just for you. Start doing that and it will get easier for you to find other ways to start living for yourself again.

Tyger Heron, I have a lot of respect for TheRealCallie and his advice, but in this case I have another perspective for you to consider.  Read fully and carefully what I say though, because it'd be easy to misinterpret my point.

As a Christian, I don't believe we're here to pursue our own selfish pleasures in life.  God put us here to know and love him and to love others.  Most of us naturally, without trying, seek to please and satisfy ourselves each day throughout our lives, whereas it takes a conscience effort to notice and care about others.
 
I don't think it's wrong to work, play, and perform life activities that give us personal comfort, pleasure, or satisfaction (as Buddhism teaches).  I certainly did my share of that with an extraordinary life of fun work, vacation trips, and outdoor recreation.  As a single, I had the privilege of being pretty selfish with my time, money, and pursuits. As I've grown older, wiser, and stronger in my faith though, I now appreciate the proper goal of focusing less on oneself and more on others.  That's what love's about.

In your case, instead of suggesting that you gave too much before in a relationship that didn't give back, I'd try to accept that you did right in giving more than you received.  The problem wasn't your giving too much, but that your partner didn't reciprocate.

While I agree that you should learn to enjoy life independently, I would not encourage you to intentionally pursue more selfish values in life  - ie, caring more about you and less about others.  In fact, I'm confident that our Creator, Lord, and Savior wants us to do just the opposite - to give unconditional love to others as he's done for us.

It's hard to give to others who don't reciprocate.  I deal with that all the time by writing friends over many years that rarely write back, by visiting people that never visit me, by listening and showing interest in strangers that only talk and never listen to me, etc.  Selfishness is prevalent, and it's a true test of one's heart and nature to go though life each day and consciously be a giver rather than taker.  But that's what love is, and that's why God put us here.  Consider this temporary life here as a training ground for what's to come - for us to learn how to love.

So, I'd suggest that you go ahead and seek some pleasure or fun each day for yourself, but I'd also encourage you to intentionally try to focus on others and find little ways to show love and kindness.  Don't worry about giving more than what you get back. Don't hold back your heart or generosity.  The eternal rewards awaiting for us in heaven far outweigh any of the temporary pleasures or sacrifices we encounter here in this earthly life.