In love with best friend and idk how to leave?

I already know he doesn’t want anything long term with me because we a have different denominations (which doesn’t bother me but apparently to him it’s a deal breaker) we have a very strong emotional bond to the point where others point it out. It’s literally like we’re already dating but without the physical. However it’s gotten to point for me where it makes me sad, jealous and hurt. He’s seeing another girl who I know, which has been really hard to see. I’m also going chemotherapy for cancer at the moment, so I’ve been sad about a lot of my relationships fading. A lot of my friends had been scared to see me and faded away however he really stepped up and did a lot for my family and I. I’m at the point where I feel like I need to distance myself so I can move on but idk how since were are friends and can’t just break up. Any advice I feel like a horrible person?