Bf cheated on me while pregnant

I found out he was having sex with someone else for majority of my pregnancy. They don’t talk anymore since she told me about it. They were actually having sex before me and him began seeing each other so he basically cheated on her, kept her around n started seeing me. We’re trying to work on it and we love each other but I feel like I’ll always remember he betrayed me while carrying his baby. This is his second son but my first baby. Since they completely stopped talking should I have faith in the relationship or is this the beginning of years of heartbreak ?