Would a woman marry a man even if she's in love with another?

I dated a girl who left her ex boyfriend of 4 years for me(they were each other's first loves but he cheated on her). We were together for about a year and a half and we had good times. We had an intense passion for each other. We couldn't resist each other. We were in love. We even discussed getting married someday. She wanted it sooner, while I wanted to wait until I was done with college and had my career going (she's 19 and I'm 20). Recently, she broke up with me, and I found out that she got engaged to her ex while she was dating me!! Turns out she never really stopped seeing him, but she didn't want to get rid of me either. I talked to her to today and she told me that she is still in love with me, but that she can't talk to me anymore in order to make things in her current engagement work. I asked her if she really had wanted to marry me, and she said that she did at one point. She told me that reality eventually hit her and she realized that there was no way we'd make it that far (because she thought my family wouldn't allow me to marry her due to their hatred for her, and because I didn't want to get married until later in life and other obstacles). However, she said that she just couldn't let me go. Then, she said it wasn't wasn't necessarily about him being the right person for her, but it was about being the right situation. So could a woman actually marry a man even if she truly wanted someone else? Was she waiting for a commitment from me and just took his offer because she assumed she wouldn't get it from me? And why does she still confess that she's in love with me?