Help! He's obssesed with his penis and I'm silently going crazy

My fiancée is my best friend and we get along better than our friends or family relationships. There is one problem I've tried to overlook but if I have to deal with it again I'm going to lose my fucking shit!!!!

Out of the corner of my eye I'll catch him, or hear him, or have him stand over me playing with his cock. It is huge I'll give him that, but he will jerk it while saying aloud how huge his dick is and won't stop even when I respond yes it ishe'll keep doing it!!!

I tried ignoring him, changing the subject, leaving the room, putting on headphones, watching videos but he keeps doing it! FUUUUUUUUUUCCKING HELL

I understand that its great to love yourself but 3 years in its fucking annoying. tried jokingly

telling him enough already and he was really hurt. I don't want to hurt him but his cock and porn obsession is making me look him differently.

I don't want to leave him or hurt him. Please help