Having panic attacks during sex

I am in a long term relationship with my boyfriend. I'm also currently going from my alcoholic husband. My current partner and I practice bdsm. Over the last 2 yeas I can say maybe 3-4 times have I had anxiety during sex (always when he was on top in missionary position and never during any kind of "scene"). But it never escalated to the panic i have started to have. Before we try anything new we always talk it through first, what turns you on, why, what are you trying to get out of it, etc. and then again after...was there anything you didn't like or did, made you uncomfortable, etc. We have been working towards more and more aggressive sex at my request/urging. My partner has been slowly increasing the intensity of those sessions. Two weeks ago we had a particularly aggressive session - the most aggressive thus far. I was on my stomach and he took me from behind and was rather aggressive, holding me down as i struggled against him. It was very intense but gave me the release I wanted. I always felt safe and knew I could stop him at any time. Later that same weekend I experienced a full blown panic attack while he was on top of me in missionary position. It happened two more times that weekend. Now this weekend we started out fine. Made love (nothing aggressive) in missionary no problems. It was an emotionally charged session in that we really connected and i broke down crying as did he. Later he was on top of me and full blown panic ensued. We have and continue to talk it through. He's afraid it's his fault, that he pushed ne too far. I've no history of of sexual/physical abuse. But am going through an emotionally charged divorce. It seems whenever i have to deal with my ex these issues surface in that I have anxiety to panic during sex. Like I said we are talking it through and he stops as soon as I start to get anxious, distracts me and helps me with my breathing, etc. just wondered what anyone else felt about this. It's frustrating and I don't want it to become this viscous cycle.

I've always found it harder to hold off orgasm during missionary, because I feel it's more intimate and less able to detach myself from the act... so my question would be, since the panic is happening during what should be plain vanilla sex, do you think intimacy issues are involved in the panic?

Yes it is during vanilla sex. Almost always when I'm on my back, i start feeling extremely claustrophobic and it escalates. I've had two episodes on my stomach with him from behind, but they have never escalated to a full blown panic attack or where we had to stop.

I don't feel it is an intimacy issue as I feel very safe and secure with him and an able to open up to him. I never have to "hold off" orgasm i love the connection we have and welcome it.

Oh okay well I just wondered.... but then, the word, 'claustrophobic'... do you get that way, in tight non-sexual situations? What I'm getting at, is I was wondering if when things get too 'close', that because you're going thru a divorce and stuff, you start feeling like, whoa! Too close!

I am claustrophobic. But have worked through almost all of those issues and haven't had problems with that for over 20 years. But i also wondered if it is rearing it's ugly head due to feelings of loss of control while dealing with my divorce.