Has anyone else experienced involuntary abstinence in their marriage?

My husband and I have been married for almost eight years. We haven’t had sex in over a year and I’m perplexed as to why. He just isn’t interested and essentially refuses to discuss it - he’s always tired, stressed etc. I’m not a nymphomaniac or anywhere near it, but I am feeling a little rejected. He barely even kisses me anymore. The more I try to explain it to myself (is it me?) the more I feel hurt and then angry. I just do not know what to do to help the situation. Any ideas? Have you been through this? He refuses any initiation from me. Please be gentle with your comments, this was very difficult to post.