So, here's the thing: those things you listed (anal sex, spanking, people engaging in BDSM) are some ways of being sexual, of having sex. They are not the only ways, they are just some, of very, very many. Some people like one or more of those things, some people don't like any of those things. Some people like those things at one time of life, or with one partner, but not at another time, or with someone different.Maybe it’s the way I react to him that stops him opening up but I don’t understand spanking, anal, or being dominated or any of that stuff I just find it very disturbing if anything, what happened to just sex?! I thought it was very simple and romantic but It’s just all very complicated for me and I obviously want to satisfy him but am I hard to work with? Does he want to explore stuff like that? I guess it frightens me that much that I avoid talking about it worrying what the answer might be.
I don’t know if you get many people like me not been interested in them things, I get dressing up kind of, it’s like guys in suits for girls but anything after that just creeps me out. It’s kinda an eye opener for me realising that my problems about sex could be the answer to him being quiet, I’m afraid of what he’ll say if I ask and in return I don’t know what I’d answer!
I’ve been exploring on websites for seducing and sex advice on ‘turn on’ points I find it hard to believe they actually work, have I got a low sex drive? I just find it takes a lot for me to get turned on.
I'm not sure what "just sex" is for you, or what it means for sex to be "simple and romantic." But I feel positive that whatever that is, there is certainly someone else in the world (and probably millions of someones, truly) who also wants and likes to be sexual in whatever those ways are. The way to find out is to do what you can to get more clear about what all that means: to be able to really talk about what you want and don't, and what you like and don't, and then to tell that to a partner and for them to be able to do the same with you.
I think you also need to remember that in order to get what we want sexually -- and overall in relationships of all kinds -- we have to be willing to actually say what that is and not try to just do what we think someone else wants. That means we have to risk putting what we want out there, and risk having another person tell us that that's not what they want, and thus, risk both of us discovering we're just not a fit, and going our separate ways. Then we keep doing that until we find the people we fit with, you know? Of course, that means we have to risk not being with anyone sometimes, or not being with someone we otherwise fancy or even love, but who just isn't a good fit for this kind of relationship.
Lastly, getting turned on generally involves having things happen that we, personally, find arousing. From what I can gather, for most of this relationship, you were having sex you did not want to be having: that's not something most people find sexually exciting (it also is very depressing or even traumatic, and depression and trauma often shut down sexual desire). Communication about sex has been totally shut down: also not a thing most people are going to get turned on by. You haven't felt seen in what you want, or like sex really was about you in any way: once more, not exactly a setup most people find sexy. My point is that it's super unsurprising to me you haven't felt a lot of sexual desire in the last few years that you have been in this, because nothing you have described in this as a sexual relationship has sounded very likely to be arousing or appealing for you.