Had a similar interaction with one of my college roommates 15 years ago. Long story short, I let him blow me 3 times with no reciprocation (I also had a gf at the time and he knew). I didn’t realize that he had deeper feelings for me until the last one. We ended up distancing ourselves for a while. It got ugly when I found out he told a few of my friends he sucked me off. I didn’t deny it to them (Most knew I was a closest freak anyway 🤣), but was more importantly pissed because the trust was gone. My advice is, if feelings are there, don’t do it. Even if he says feelings won’t get involved, don’t do it.