I Have To Stop It, But I Can't

This has been going on for a few years now, and I'm just going to say it like it is. I'm sleeping with my own son. He's half my age.

His father and I divorced when he was very young, and of the two parents, I was the least suitable to care for him regularly (I was the more economically sucessful, but I was incredibly busy). So he lived with his father most of his life, and by both my son's and my own admission, I never became that much of a mother figure to him. Eventually, I resigned myself to that fact and even took a job abroad. His mother figure would become my ex's next wife.

However, we stayed in touch, and when he got a scolarship to study abroad about 5 years abroad, I invited him over to stay at my place. I felt a need to connect with him, I had the spare room and wasn't around the house much, to be honest. So we did that.

Our relationship started awkwardly but friendly. We knew we were mother and son, but our relationship felt more like that of respectful roommates. It actually started warming up over our respective partners, to the point that we eventually invited them over. Funny thing: he was secretly dating a teacher about my age, and I was dating a man 10 years younger. We started to be more open about our lives, sometimes our partners stayed over (and had sex, which was very noticeable any time it happened).

By then I could tell that there was a pattern with my son, because I could notice him watching me sometimes, especially when wearing my workout clothes. Modesty aside, I was always a very desirable woman, and have taken measures to keep it that way even at my age. One night, I asked him about dating older women, just to tease him. He said there was a sexiness to the maturity and experience of women who know what they like and want.

"... and you give away that sexiness too", he let slip.

At first I was shocked, and he was looking at me with such intensity that it kind of embarrassed me. When I asked him why he'd say that to me, he just looked away and said he was sorry, that he just wanted to compliment me and didn't mean to make me uncomfortable. And in such an awkward note the conversation was over... but I couldn't stop thinking about it. In time, I noticed I felt an attraction too. Neither of us was dating by then, and our relationship wasn't that of mother and son, no matter how hard we tried. It was a tempting thought I held back for a very, very long time, to the point it made our daily interactions awkward. But it always came back: "what if I indulge him?".

I gave in the night we celebrated his graduation. I intentionally kept pouring wine in our glasses, so either of us could gather the courage. When I threw myself at him he didn't even flinch. On the contrary, he threw me like a rag doll on the bed and I let him have his way with me. He knew exactly what he was doing me, and pleasured me like no lover had in years, before cumming abundantly inside me as I climaxed. I hadn't felt such connection during sex before, such arousal at doing something forbidden. We were a shaking mess of sweat, spit and cum at the end of that first time, and no guilt in sight. We could not get enough.

I obviously know this is not ok, and he does as well. But it is so addictive we have both tried to stop it, without success. Even after he moved out and got his own place, we kept coming back. We've dated other people, but now nothing else compares. And it's getting out of control: a friend of mine walked in on us about a week ago, and while she wasn't accepting, she kept it to herself. I don't know how to stop this, but I'm too ashamed to see a professional about this...