Advice pls

I've been dating my boyfriend for almost 5 months. A couple months before we started dating, I had a crush on his ex best friend (they stopped being friends Bc he stole all of my current bf's girls from him). He has been one of my best friends since then and he has feelings for me but said he's not gonna act on anything Bc he feels sorry for my current bf. I'm starting to like him back and I feel bad about it. What would you do??? Help pls