I was in a similar situation with my first DH. He was my first long term boyfriend, and he was a lovely man on many counts, but a very selfish lover, and totally insensitive to my needs - which were mainly to be treated as a human with feelings! I did used to communicate my needs to him, but you can't make someone be affectionate towards you, it really has to come naturally IMO. Sex was very mechanical and all about his pleasure - no emotional closeness at all.
I went from really enjoying sex at the beginning of our relationship to a position at the end where we very rarely had sex, but he constantly badgered me for it. I did go through a phase (a year or so) when I continued to have regular sex because I felt I should. Looking back it was totally soul destroying and made me hate him. By the end I couldn't stand him touching me.
In hindsight the relationship went on much longer than it should have done, and I put up with way more ill-treatment than I would now, because it was, for both of us, our first major relationship, and we really thought we were meant to be togather.
We split up and I went through a period of dating (had sex with a few new men!) and do you know what I discovered, there are other men out there who are just as insensitive, but also some who are genuinely affectionate, loving and sensitive to your needs, and who wouldn't dream of having sex with you if you weren't totally comfortable with it. Sex became enjoyable again. More than that though, I was much happier in general, being free from a bad relationship. I didn't realise quite how much it was affecting me until I waqs free of it.
I am now in a relationship with a man who I love, who's sensitive to my needs, and has become by best friend, and it's the best thing ever. The sex is great as it's based on a love and affection. And if I ever simply don't feel like it (or he doesn't) it's just not an issue.
And my ex? Well we're actually good friends now (although I do feel sorry for his new wife, I'm just so, so glad that's not me any more!)
Please, please seriously consider leaving him, soon - although it seems like you are already. It may be hard at first, but you really do deserve so much better than this. And your children deserve to have a mum who is happy.
Good luck