Discrepancy in sex drives emerged after marriage

For over a year, the man who is now my husband and I had an overwhelmingly passionate romantic and sexual affair. We made love every day, held hands like teenagers, kissed for hours. (We’re both middle-aged, I should add; the intensity surprised us both.) We’re very well matched in other ways (intellectually, professionally). He wanted to marry me, which came out of the blue: I wasn’t seeking permanence, just rapture. But I said yes, because I thought I’d finally found my match, my mate. Once we moved in together, though, his sexual desire for me suddenly evaporated, while mine didn’t change at all. He’s happy to have a companionate marriage & feels embarrassed about his lack of sex drive but said that’s really just who he is–that our wild year was a wonderful aberration for him but that now he has settled down into our quiet, companionable life together, refocused his primary energy on his career, & is content. He says he loves me and doesn’t want to break up. Meanwhile, I’m going quietly nuts. Is he a crazy toxic weirdo? Should I head for the hills? Or should I expand my definition of marriage to encompass what is rather than what I thought would be?

C: We’re not having sex. I am a person who loves sex and would like to have it every night–and then some.
T: This is unfair. He deceived me. OR Something’s wrong with me: I’m too old, I’m a turn-off, I’m not beautiful, he probably wants younger, hotter women; once he got to know me better, he perceived some deep flaw in me. He takes me for granted.
F: Frustrated, pissed off OR Sad, self-loathing, despairing, and lonely OR fearful, paranoid, & jealous about other attractive women who cross his path (I oscillate among these 3 perspectives. All seem potentially valid–and, equally, potentially invalid.)
A: Grumpy withdrawal OR Pathetically needy attention-seeking, being “cute,” lavishing him with praise & affection (& then feeling irritated when he doesn’t respond in kind)
R: Well, it sure ain’t sex. Sigh. More like a weird, semi-affectionate detente with frequent good conversation–underlain by my simmering frustration & feelings of having been unfairly misled and then rejected/neglected.

Should I leave? Or should I let go of my manual that says he should be providing me with erotic bliss on the regular? Could *I* be the toxic, crazy weirdo in this relationship? Acting inconsistently (A line) in response to different thoughts that explain his behavior (T line) makes me feel unstable, but I can’t seem to land on a steady explanation or way forward. Help! The crazy part is, I really do love him and find him fascinating and want to make this work. My feelings of frustration have not (yet) been strong enough to make me want to quit–and, given the advice from Brooke, et al., I don’t want to quit unless/until I’ve gotten happy. But this situation is baffling and crazy-making. I welcome your advice.