Thanks for all your responses. I sort of feel like I want to defend him!
He was sharing personal stuff with me in the context of my being a good listener and being WILLING to listen to him. I was able to give him some tangible things he could do to improve his marriage. He is at a vulnerable spot in life, and I pointed this out to him as well. His age, kids at college, not close to his wife, menopausal wife, midlife crisis, etc. I advised him to put off making huge decisions about anything, and not do anything that he'd regret later on.
He did not know at that time that I had a huge crush on him. Well, I decided to tell him and now we can joke about it. When I told him, it obviously pleased and flattered him which was nice. I told him not to worry as I'd get over it.
We remain close friends, still talk about everything, we've both "been there done that" sort of thing, and continue to share our experiences.
I am too much of a feminist to betray another woman by interfering in her marriage. Just let me put that out there.
I'm really not looking for anyone and don't feel deprived of love. I do miss sex however, but that's another thread!
Occasionally, if I meet someone who I think am attracted to, I think to myself, it would have been nice if we had met a long time ago. I've had my children. I've had one bad marriage and I'm not looking for another. In fact, my ex-husband was so bad, that I never want to put myself in that position again. If Prince Charming does comes along, he will have to come with a chorus of angels and a marching band to get my attention.

Best,
Okie