I wonder if my boyfriend is gay..

So my boyfriend and I have been together for 4 years and 3 months and when we first started dating we had A LOT of sex (multiple times a day) and I took his virginity and he was really good in bed. As the years went on his sex drive decreased a lot, we now have sex 1-2 times a month. He also became interested in trying new things with me which is totally normal but it's all things I would assume a gay man would be interested in.. He asks me to finger him, give him rim jobs ( I refuse) and asks me to let him taste his cum.. I've been with previous sexual partners and I have never encountered these things in the past. He often asks me to dominate him, and when we fore play he does a few things to me and asks me to do them back. He likes getting choked, slapped and kissed/licked from head to toe.. It's very uncomfortable for me and half way through our sex I get weirded out because I'm constantly questioning if he's gay or not. I just want him to be honest with me because we're both at the age that we would want life partners and I feel like I'm wasting my time with him if he is gay.. Any input on this would be awesome. Thanks guys