Please help! I can't manage to separate myself from an unavailable man

I am confused about the word love and so i will sometimes use words like care, want, like.

I am 26. I have suffered of deep depression for way too many years. I'd say I haven't been myself almost 10 years. In this time I lived inside of me and I suffered madly, like I think my head should have exploded of that much sufference, loneliness and fear. I can't explain how much I suffered. It just shouldnt be real. I think depression is too soft to describe it. Among many many other things, I was feeling unfit for this planet. Like I belonged to another world, I was that far removed from reality. It's a miracle that I recovered. And it's thanks to a man that I started therapy with. We did therapy 2 months, during which he wasprofessionally distant, talking with Miss.. I started to love him from therapy but I didnt say anything. I had no idea what was going on with my feelings. Anyway, after therapy we became very close. We clung one to another. Now I am strogly attached to him. I love him with all my heart. I am grateful to him very much and I want to pay him back with all the kindness and goodness in the world. I sometimes suspect that my love is born out of gratitude, but I also might be atracted by him as a man. I want him. I want to be with him. I dont want anyone else. He is also attached to me. He says I saved him back. We are kind of madly in love one with another. But it's not clear for me if it's pure man-woman love or something born out of the fact that he one time was my hero.

My difficulty now is that he is not available so that we could try a normal relationship, to see what is really going on between us. We cant live together, go on dates, hold hands in public, spend time freely, doing nothing or doing routine things, to see if we would stay together and care about each other no matter what or not. It's hard for me to mention it, i dont know why: he is married and has two adopted children with her. His wife is a decent person who seems like she would die withouth him. And he says that she has been with him through times when he wasnt that decent, and can't abandon her, wouldnt be fair to her. They have their bond based on having been young together (they are both 40 now); he says he was smitten with her when he first saw her. Now he doesnt seem in love with her or attracted, but i suspect that this might be the effect of having been a long time together and that their love, which maybe at the beginning was sparks and poetry now has the shape of something else, like reliability, respect, .... Maybe this is what happens with loving couples in time.. I don't know. But at the ame time he seems very in love with me too. Maybe it's because I am young and attractive, I am interesting to him, new, and mad about him, so he gets a lot of attention from me, feels important to me. but, at the end of the day, the prpoblem is that we can't get sepparated. its like we both see that it wouldnt be right for him to give up on his already built family, I don't want to see that happening either, but at the same time I am crying after him. I want to hug, caress him, support him, take care of him like he was my man, and I want him to hug me and carrry me in his arms and only love me.

I don't know whats wrong with me, but I can't go on with my life. I am stuck. I don't want anyone to suffer, but if i step away and force myself to not contact him I can't make it very long, I fail to stay strong in 1 day or two.... This is it for now, forgive me if I wasnt very clear. It's hard to depict this picture. I don't see it clearly either. Maybe we can discuss about it, I can answer questions, and with time I'll figure out what's this relationship's place in my life.