Is leaving the relationship bad for the kids?

I have been in a relationship with this man for 4 years. We have a son together who’s almost 2. But I’m not happy anymore. He’s a great man & father. I respect him so much but the attraction is gone & I’m not in love with him. I see him more as a best friend. In my head I go back and forth. I feel like because the relationship is good I should just stay & be unhappy for the sake of my son so he doesn’t have to grow up in separate homes. I want to leave but then the guilt of hurting my son kicks in. I also have guilt because I’m in college & he put his career on the back burner so I could continue college. I also have guilt because I got gastric bypass & lost a 100 pounds & I know people are going to think I left because I lost weight but that isn’t the case I wanted to leave a while ago but I keep pushing through for my son. I don’t know what to do. All these cons & the only pro is I’d be happier. I feel selfish & I need advice.