Am I the one that caused our relationship to fail?

This girl at my job sent me a message on facebook basically asking me out. We started seeing each other almost everyday and fell in love. I tried to talk to her on the phone but she preferred texts which should have been a warning. She had a daughter which I was totally fine with and she told me she loved me first. I had my guard up all the way to this point, but I let it down all the way as we talked about cheating and how we've both been hurt.(Another girl she knew there hurt me). Everything was going along great until one day she tells me she can't see me anymore. Keep in mind things were pretty good granted we had our differences with one another but I could feel how much she loved me and I in return. I always told her compromise is a key component to long term success. She was crying and hurting inside I could tell so naturally I was wondering what caused this. As we stopped seeing each other slowly but surely things went south. She always found a different reason we couldn't be together. It was almost like she was trying to convince herself I'm no good for her. She then told me she was pregnant and I said it wouldn't be best to keep it not because I didn't want it but because our relationship seemed to be falling apart and it wouldn't be fair to the baby. After she said she had an abortion which I'm not entirely sure of I tried every way to put the pieces back together. In the end I found out she was seeing her ex who is filthy rich when she wanted to break up originally. She had flown down to Louisiana for 5 days to see his ailing mother and I'm told this is when they made up. When she got back is when things really got weird like random accusations, mysterious calls, no time at all for us, but yet she kept it going with me. Why After she made up a final reason not to deal with me she sent pictures of an engagement ring to my co workers. This is why she couldn't see me anymore but she kept acting like she wanted us to work out. Why is that? It's tearing me apart inside and I don't know what to do. She won't admit it either. She keeps making it seem like I'm this deranged individual when everyone else sees what I see....Even strangers! Can someone please break this down for me tell me what I did wrong?