I think you have to figure out what bothers you about it. Do you think he gives up on people? Did you have hopes of giving him his first child? Are you afraid that whatever went wrong with that relationship will go wrong with yours? etc.? Once you figure out why it bothers you, you can start to deal with it.

to be honest its personal choice. if you can cope, make an effort.she's probably scared of you, unsure where she stands and finds you strange. Take her out for a girly day, make an effort and invite her over to have dinne with you and her boyfriend.