Shattered beyond belief

I've posted here before about it, but my girlfriend of 5 years has been cheating on me nonstop and has finally decided to leave, I'm beside myself with grief and a mountain of debt from the relationship that is just unreal, I wish I could make everything better but I cant, it all happened because she cant stand my son from another marriage, how can someone hate a child so much that they would make the father choose, the choice is simple...