5 years and a baby girl, How do I deal with it ending?

I met my now ex 5 years ago and we got off to a great start. We were together all the time and life was great. She was my first serious relationship, and I thought "wow, I got lucky". Within 4 months she was pregnant, and after the baby was born, I asked her if she would marry me, which of course she said yes. Only problem was I really didnt want to. At that time I had cheated on her a few times, for purely sexual reasons. I didnt know what to do. I decided to dedicate my life to her and my daughter. Over the next few years we were very rocky, but I thought we were going to make it. A few months ago she started seeing her best friends brother. She assured me they were just friends, and I knew him, so I had no real reason not to believe her. After getting some information from someone she knew, I learned that she had cheated on me before, and when confronted with it, she told me she had done it to get out of our relationship. Had she fell in love with someone else, she would have left me a long time ago. Well now she has fallen in love with someone else, and I am out. I have no Idea how to deal with this, and the fact I have to see my daughter makes it so much harder. I grew up in the foster system, so I really dont have the "family and friend network" I hear about so much. I really am on my own. Its not fair that I loved her with everything I had and I end up like this. If anyone knows of anyway to help me, please respond.

Well, you know it looks like you got what you wanted in the first place, only that she was the one that beat you to the door. im sorry if im a little direct, it seems to me that something was missing from this relationship from the very beggining.

This breakup is gonna be painful for you for sure, being young and having little previous experience with relationships, its gonna be hard.

Be strong, be a loving caring father to your little girl, and try and learn from the mistakes that were made, and do better the next time around, dont try and make every relationship work "no matter what", find out what your looking for in a partner, be yourself and youll find someone thats just right for you eventually.