I'm dating a great girl but I feel stuck. I am suffering from what I'll call "chemistry comparison awareness and fear of loss". I'll explain.

I dated a woman in my past for a long time, on and off (like from the ages of 22-34) because the sex/romance was completely awesome. Her touch was electric, her kisses sublime, we could not be in the same room alone without getting naked. She was so feminine and sexy and sensual and touchable and simply beautiful, I rated her an 11/10. I memorized her curves, her likes and dislikes, I was basically obsessed with pleasing her and I inspired her to respond in kind. I finally broke up with her because (not that this matters, but let me finish) her IQ was probably at least 50 points below mine (I actually caught a couple hints that she might have been considered "learning disabled" at some point during her schooling... Both her parents have PhD's so it was kind of hard to believe). What would happen is that the more time we'd spend together, the more... claustrophobic I would get, and the best I could come up with at the time to explain that feeling was the intelligence difference. I would want to talk about something at a certain level and I would get frustrated. I didn't always have nerdy friends to rely on for this outlet so it bothered me.

Anyway fast forward a few years since I last saw her. She lives in California with a dude, I am probably about to let a woman move in with me. (The irony is that this new woman is only a bit more intelligent [albeit not nearly as attractive, at least to me], she's funnier and much more responsible tho, a way better cook... but this fucking chemistry thing is a motherfucker to mentally get around :/ )

The chemistry with her is far inferior to what it was with this other woman who I put on a pedestal because she seemed completely out of my league and then I miraculously achieved sustained carnal relations with her. Where once I could not be in the same room without getting sexy out of my system, with this current woman it's take-it-or-leave-it most of the time. Maybe I'll try to bang her, maybe I won't and go to sleep, maybe I'll just kiss her goodnight and then go play Diablo 3. I feel the relief when the sex is done but not that WOW THAT WAS AWESOME feeling I had with the other one. (It's plenty affectionate, though. But I'm an affectionate dude so I always bring that out of my women :) ) I fantasized about the first one when she wasn't there; I've barely fantasized about this one. When the first one would spend 20 minutes just getting ready for bed, I would lie there panting for the inevitable sex like Pavlov's dog, and if she withheld sex for some trumped-up reason I would get angry and do everything in my power to make it happen (and was usually successful); with the second one I give her a neck massage, roll over and pass out. You get the picture. She doesn't even seem like she wants to go down on me that much, and when she does it it's very "meh" (and honestly I don't nearly want to go down on her as much as I did the first woman), yet she says she "REALLY loves me".

And I think I'm hung up on the aura of the first woman. Her name still appears on my lips often. And through a mutual friend I found out recently that we are still kind of pining for each other now and then, separately. (I am not in touch with her currently, however. We made that decision quite a while ago.)

This is the real reason why I am 40 and still single. I am even second guessing the choice I made to even have sex with that other woman to begin with originally, because I suspect that some kind of low level biological "sexual imprinting" occurred. At the time I was in a pretty low point of my life and she was there for me and (despite being less intelligent than I would have preferred) super hot, and I could not wait any longer at the time for "something better" because I was a hard-up 21/22 year old. And it was very very good (extremely intense), so I did not want to stop despite my misgivings about it all.

I don't know how to get past this "I may never experience that level of chemistry ever again if I commit to this new person long-term" thing. I feel like my brain has made her more or less my permanent "sexual object" and other women will just not cut it enough. Or at least, any women who want to date me. And that is extremely depressing.

I don't mean to sound superficial, I have dated a number of wonderful women in the meantime who were much smarter, almost as good looking, and in some cases had much better personality qualities (objectively). (But of course, I wouldn't be here on r/ra if they worked!) On some level I am seriously worried that I am "permanently hooked" on some irreplaceable aspect of this Ur-woman who I dated for so long.

I always get to a point in a new relationship where I get like this. Usually it causes it to fail, and it's officially a pattern. It's going to happen again. Help :/