How do you justify leaving your fiance for another girl after she refuses to have an abortion?

He obviously wasn't a nice guy- or a mature guy, or a man worthy of being a father. He liked to idea of playing house, getting engaged and getting married but probably didn't have the maturity to follow through. A lot of "nice guys" aren't really nice, they're manipulative. When something happened he didn't want to deal with, he ran off for greener pastures.