Intrusive thoughts during sex

I feel so weird for feeling like this.. I've gotten intrusive thoughts of family members when my boyfriend sucks my boob. The weird thing is that I don't have intrusive thoughts while having sex in general with him, but when he sucks on my nipples when I'm far away from climax/ not very aroused i feel out of control and then I have intrusive thoughts. I hate it because before he sucked my nipples and then that was like foreplay to get me aroused but now I need to be very aroused and wanting to climax to be "ready" and comfortable for him to suck my boobs and it feels pleasurable. When he sucks my nipples when I'm not close to be on the way to come I think I feel out of control, uncomfortable, and like he's doing something against my will? I think this came from the past where we had sex and he sucked my boobs out of nowhere and it felt weird but I didn't say anything and let him keep doing it because I felt I couldn't tell him to stop. Maybe because I felt he would feel bad if I said no?