I have the same theme, but a bit different each time. All the same key elements are there though. I will try to remember them all.
First off, the person in my dreams is a boyfriend I had in my teen years. We were young and prude, never even kissed him, but the intimate tension between us was intense. (Think, the twilight movies) We did meet up a couple times as adults, once he got back from serving overseas. The tension was still there, but neither of us acted on it. it ended with him not ever calling me back, and I decided to stop wasting my time.
ok, so that's the guy. Always in the dream we are kissing or making love to each other and it's very intense and passionate. Then, out of nowhere, he disappears, and I go searching for him. I pace up and down (sidewalks, ocean shores, neighborhoods, etc) looking and looking, then never seeing him again. I am left longing for him. This is the point that I usually wake up. There are times when I find some sort of clue while searching. Like a letter, a mutual friend or book. In last night's dream, I heard someone talking of a book, and all the characters were actually me and my friends as teens. It told all about us, and what it was like (the tension, the friendships, etc) I wanted that book so bad, so I picked up a flier that was on the table and it told where to find the book. Except all the places showed it as a clearance or out of stock item. I started rushing to find this book, and then I woke up.
The book was called trematek (or something similar in spelling, because I kept refocusing on the word and trying to figure out how to say it)
Usually I try to go back to sleep, because I wake up feeling all this tension, and want to resolve it.

I have some ideas about what this is about. Obviously this is an unresolved feeling of mine. I never knew why he just stopped answering my calls. I have a lot of questions about that. I also feel bad because I called him multiple times before I caught a clue.
Our relationship was very limited (as stated before) and he often didn't treat me right. He would talk dirty to me for shock value, because I was very naive and innocent. ( liked it but a good girl doesn't let on to that, so I would walk away, or yell at him)
My current relationship status... married. To a man with erectile dysfunction. I think that plays a part too. I am not satisfied in my marriage, but my husband says all the nice things that a man should say to his wife. I never dream about him pleasing me... I've wished I could, because I wake feeling guilty that I am dreaming of another man. But no... if it's got sexual tension, it's the other guy.
Anyone got any clues?? I really would like to resolve this and move on.
dreaming of another

Also wanted to add, that I often become aware that I am dreaming, while in the middle of it, and try to stay in the dream, cuz it's awesome. This is often the point where he disappears, or turns into a manikin or something that I am kissing. (sad, I know) the search is on, and I know Im dreaming, but I keep trying to find him in the dream again.

I agree that the dream could be about you not being completely satisfied with your marriage. it could be a way of relieving sexual frustration that you are experiencing in waking life.

It could also be about wanting to go back to the past, when you were younger and didn't have the same problems that you have now. Your ex-boyfriend is a symbol of the good times you had in your past.