Thank you all for your comments. I had forgotten how good it feels to get the support of all of you.
Divorce is definitely not being ruled out, but we both are very fond of and attached to the life we have built together, especially the family we have created with our 6 and 10 year old daughters. I bring my problems here, but the fact is we do a lot of things well together. I can't imagine right now any life apart from him that would feel better than what we have together. I don't want to live alone, or elsewhere. I don't want to just be with someone else instead of him. I want to be with him, and I want to make the best of what we can be together. That at least is our goal for now -to try to make our marriage as good as it can be, given our differences.
I suppose I should let go of the dream of being married to him for the rest of my life. In fact, in counseling last week he said it was not something he thought he could do. (I was shocked and crushed.) I know I can't be happy acting monogamous forever, especially with someone who loves so differently from me. I think we owe it to the kids to at least see if we can make this work for now, though. I don't mean "stay together for the kids" but rather "attempt rediscovering happiness together, for the kids and for us".
On a brighter note, C (can I still call him my boyfriend?) came to town for a dance last night, so we first had several dances together in which we carefully refrained from bursting into tears, and then went to a pub where we had a good long talk. The way he sees it, we are just taking away this almost superficial aspect of our relationship, the physical intimacy, but he is as committed to loving me as ever. When I reminded him of the difficulty we had in the past trying to find time for each other (he lives 5 hours away) and that without overnights we would be back to this very random infrequent way of seeing each other in passing, he said he thought he could change his lifestyle in order to spend more time in my part of the state. I was surprised, given that I can't offer him a physically intimate relationship any more. He said I have become an extremely important part of his life, and intimacy or not he wants to keep me in his life. This comforts me. We haven't really broken up. We just have to express our love differently. It almost felt last night as if we were recommitting even more, to being in each other's lives.
Sometimes when I'm talking to my husband, I feel like our differences in the way we view/feel love, relationships, life, social interactions, etc are so completely different that we will never understand each other. It's overwhelming to try. I sometimes wish that we could live together as friends and partners in raising our children, and just let go of that part that is causing us so much difficulty, having a romantic partnership. But he desperately wants a conventional life. So I will give another try at becoming a conventional wife.
Married to a monogamous man 15 yrs, mother of 2, dating C 3 yrs, and in a romantic friendship with L more than 20 yrs