I do feel pretty bad for him

So my younger sister is about 3 months pregnant with a baby she's gonna keep. She had only been with the father for about a month before getting pregnant.

She broke up with him recently because she "just didn't feel the sort of love I feel like you should feel when you have a kid with someone."

Most people's reactions are along the lines of "good for you" and "a child doesn't mean you need to stay with someone." Which is fine. But I can't help wondering what people would say if he left her for the same reason.

tl;dr--society is ***ist.