Sexless Relationship

I'm a 24yo (M) dating a 21yo (M) for a little over a year now. Before entering this relationship I had never dated anyone and I was a virgin. When me and mySO became boyfriends I was dead set on making things official, and the eventual goal of marriage. So that's the path we took. My SO has been with the gamut of people and in my naviety was shocked by it. I've been generally happy in the realtionship, but I struggle now with the personal issues of marriage when I have yet to explore my own sexuality. My SO and I never had a very active sex life, with the first 6months of our relationship being me wanting to wait because I wanted to make sure he was the right guy, and the past 9 months being little to no sex. Throughout our 15 month relationship we've had sex possibly 8 times, with some of those times being on the same day. At this point we haven't had sex since July. There were times when he was concerned about cleanliness and then there were time when I would be pushed away and there were times when he was say why dont you just ask. Which I'm not opposed too, but my image of a desirable sex life wasnt me asking for sex, and like mechanically, and unemotionally he would fufill the order. So I began to feel alot of things. 1. I became resentful, mostly because I felt rejected, and confused, because before our realtionship my boyfriend had a very colorful sexual past, why couldn't we have that. 2. Fearful. This is the only sexual experience I have ever had, if we continue on together is this what I have to look forward to. I felt cheated because I felt I was giving up the opportunity to have sex with any other person for him but our sex life was stagnant and unfufilling. So after countless arguments about this with no real resoultion we were stuck. i repressed my sexual feelings for months, that eventually didnt work. Scared that I was losing my "best years" to a sexless relationship I looked outwardly to fufill my sexual needs. I hooked-up with a few guys, but the last guy I hooked-up with scared me because I began to develop slight feelings for I stop contacting him altogether. Before you morally shame me, think of where I came from. I was a virgin originally, with full intent of bein faithful but after expressing my needs and them not being met, I began to seek other things. At this present moment I care about my SO alot. I know I love him, but I know I have more living to do. I'm afraid that if I leave someone who loves me unconditionally I'll regret it, but I'm also afraid of not having my needs met sexually in my primetime. What should I do, stay or go? Ps my SO told me he wouldnt want to know if he was ever cheated on.