I don't know if I'm going to help, but here goes.
I left someone, because he was being an arse, in January. I justified it because our relationship was shit and I got nothing out of it. Yours sounds reasonably similar.
Take any financial worries out of any decisions you're making. It's important to make an emotional decision when deciding whether to leave someone. You can deal with practicalities and money separately, once you've sorted your head out.
Take any fears about what his reaction is going be out of the equation. I thought my DH would kill himself or freak out. Actually although he was shocked and really upset, he was also relieved that the tension was over.
Your DH really doesn't sound like a very good partner, and I think you probably should feel more...assertive about your own needs. Don't feel lost - feel angry, and do something about it. Everyone deserves happiness, including you.
Someone refusing to go to Relate is really unreasonable. That's one of the reasons I left - after really thinking it through, I just thought: if you know we have massive problems and I'm incredibly unhappy, but you want all of this to work and say that you love me...you just would come with me, and try harder.
My DH refusing to go was the sign I needed that he didn't give a shit about my needs. You need to ask your DH why he's refusing to go, and ask him again. If he's still refusing to tackle your problems, you know what your answer is.
There really isn't a future for you with someone you don't want to have sex with.
You might need to wait until you're really desperate. The way I felt was this: I had to run and jump off a cliff, because what was chasing me was so fecking awful, ANYTHING would have been better, even going through the hassle, guilt and pain of leaving a man who I still sort of loved.
It's not easy, but freedom and happiness is worth it, I can honestly tell you. It's great.
Why don't you feel safe? Is that a physical concern, or do you just mean you're terrified of tackling the whole divorce thing?
Oh, and fyi, the way I tackled it was very simple and honest. I just told him I was desperately unhappy and I had to get out. I didn't say sorry, I didn't cry, I just said that was it. It really is as simple as that if you're determined to change your life.
Hope you come to some positive conclusions.
Take care of yourself.