Low sex drive

My boyfriend and I have been together for 3 years. In the beginning we used to have sex very frequently and I had such a high sex drive. Now most of the time when he initiates sex I don’t want to but do it anyways to make him happy. I hardly ever get wet beforehand and usually don’t until few minutes after we start having sex. This frustrates him and I totally understand. Sometimes he will still push it in even when I’m not wet and it hurts. I’ve been on the same birth control for at least 6 or 7 years now and he’s very attractive to me. So what is it? What can I do to help it?