Hey OP - how are you holding up? I hope your ok.
My thoughts on this through experience is that this feels awful for you as I know you probably have a series of awful images running through your head of some young taught, toned, bouncy firm boobs etc etc etc dancing in front of your dp and grinding on him. At the same time you cant help but think to yourself, no matter what your views or his views on strippers is, with these images running through your mind you end up thinking....how can he have not had at least some enjoyment out of this how can it not have been turning him on??? and it kind of makes you feel completely robbed because the only person your dp is supposed to see in that way is you, the only person meant to be turning your dp on is you! and it feels like such a betrayal.
To those that would compare stripping to porn is not even in the same realm for me, because porn is not someone in front of your man who is touching him, and who he can touch. Its a real person and that makes a big difference.
My Dp ended up in strip club (quiet some years back now) and I know he hates the places because he feels uncomfortable, but it was corporate night out with clients and so it wasn't like he could refuse. He actually had me pick him up from the strip club, he laughed when he was telling me how when he called me and told me where to collect him from that all the other guys were going nuts saying while didn't you get her to pick you up from the pub round the corner??!!! your going to be in trouble....she's going to have your ass etc etc. Anyhoo an hour after the phone call I picked Dp up from lap dancing bar and drove him home. I have to say I wasn't remotely bothered that he had been in there, but when he revealed he had been bought a dance by one of the clients I felt awful. He explained how he felt he couldn't turn in down because it was a client etc etc and I know how much he dislikes those things and all that. Despite knowing he would never go to one of these places of his own volition and that he would never pay to have a dance, I also know he is a red blooded male and whether he paid for it or not he must have enjoyed it at least a little!! I have to say I did have a massive row with him about it and I wasn't the same with him for some time after that. Even though I actually didn't think he had done anything wrong per se....as I knew he hadn't sought out to go to a strip club, he hadn't paid for the dance, it wasn't like any of it was what he intended.....what I was upset with was the fact that he might have/probably did enjoy the dance, she most likely made him hard (sorry to be crude), he prob wondered what she was like in bed etc etc and that is what I found really hurt, it hurt and I felt betrayed and I made him understand that and in the end we got over it....and now it's something we laugh about. However, if he had arranged to go to the strip club, if he had sought it out, if he had paid for a dance I do not think it is something I would have gotten over, because then he would have actively betrayed me, he would have intentionally hurt me, and been trying to get his rocks off looking at some other woman dancing and gyrating in front of him. So for me that is where the difference in forgivable and not forgivable lies.
Also OP, in the years since this happened I have ended up having some friends who are strippers and I have been to their places of work and let me tell you...none of the strippers look like pam anderson or like FHM babes, most of them have stretch marks, cellulite, bad teeth, etc, the only difference really between them and us is that they walk around with it all in full view for work. Having gotten to know some of the girls who do this job, they are all normal and just like other women, they have stretch marks because they have kids, the have cellulite because they confess to eating a few too many chocolate bars, they have hang ups about their bodies too. Perhaps most comforting though, is that all they are interested in when it comes to dancing for guys is the size of their wallets!! One of the girls told me that while she is gyrating on a guy she is usually thinking about the list of things she needs to get for shopping the next day.
I hope that helps OP, and I hope that you do manage to get through it! I am sorry that this has hurt you and I am sorry it feels so awful right now, but it does go away, it did for me. Those images will fade, and if you feel like it, you can replace them with new happy memories. The stripper was a cheap thrill (and not of his own doing), but you are who he loves, wants to marry etc, and I bet (whether you think it or not) your ten times sexier to him every day of the week and twice on sunday's because you have his heart.