threesomes

Ok ladies so I got a doozie for ya. So me and my SO have been dating for 3 years now, and plan to move in together soon. I love this guy with everything, but when it comes to sex we don't seem to be on the same page like half the time. Don't get me wrong we have Great sex, but it's usually in 2 basic positions. I've always been in experimental stuff; with girls, rough sex, public sex, dirty sex.  and I've mentioned that I want to have a threesome, ffm, but he is completely against it. Disgusted even. Lately I've been feeling very sexually frustrated, he doesn't make me feel sexy and wanted, in fact half the time I feel like we're best friends. I'm beginning to feel like we're not sexually equal in this relationship, for example I give him BJ's because I WANT TO, he doesn't even have to ask. But he won't return the favor. I used to love making out before this relationship, he told me he doesn't like it and we haven't done it since we first got together in 2014. I feel like him rejecting the threesome idea kind of opened my eyes to him being so bland sexually. Idk what to do, advice is welcome.