I don’t know what to do

So I have a friend that I’ve gotten closer to. The thing is have started to develop a crush on him, but he has a girlfriend, (I’m friends with her too, we just don’t talk much anymore) and they have a lot of issues they have to deal with, and before I started to develop feelings, I would talk to him, give him advice on things but now I feel I can’t.

I’m in a rough spot because I know their relationship isn’t healthy, she’s puts a lot of her baggage into him, and doesn’t give him a chance to share his struggles. On top of that, she’s made him do stuff he didn’t want to do.

The main thing I’m worried about is letting these feelings fester and end up hurting him. I want to keep our friendship, but I don’t think I can ever tell him how I feel. Aside from all that drama, we’re seniors. What happens when we graduate? We split off our own ways, so why tell him when it probably wouldn’t work if there ever was a chance.

The only thing I wish for right now, is his happiness, whether I’m in the picture, or not.