@swissmodel
What I find most hideous about your post isn't even the fact you feel entitled to have sex with your partner when she's not in the mood (or how can she possibly expect you to be faithful, just hanging around waiting for her to - gasp - actually feel like having sex, or even - dry heave - put some time and effort into figuring out what gets her in the mood?).
It's the fact you say if she's obviously not into it you wouldn't do it, so you expect her to pretend to be.
So not only does the poor woman have to fuck when she doesn't want to, she has to put on a porn show for you to feel comfortable while you rape her.
I sometimes have sex with my partner when I don't want to particularly. Not because he's a shitheel who'll betray me if I don't and I'm so desperate for a man in my life I'll put up with being regularly raped to keep him; but because I know it is very important to him and I want him to be happy and for me it's a "would rather not but I'm ok with it" not a "I will genuinely feel awful if I have sex right now" thing (just so bloody tired re small kids, sex if done right for me requires a lot of energy I don't always have).
He knows this. So if I suggest/acquiesce to sex when I'm obviously not already "in the mood", he will put serious effort into making it pleasurable for me, or if I let it be known I'm up for a quickie for his benefit but not a sesh as it's just not happening for me he will move things along accordingly. Because he appreciates I'm a human being not a fuck doll, and a modern woman with rights and feelings not a dependant he has bought the rights to from my father and can do what he likes with.
And I don't have to wail and moan and put on a show or "pretend" I'm enjoying something when I'm not so his ego can cope with the fact I don't always get a thrill from sex with him. He's gracious enough to appreciate the gesture without me putting on a floor show.
And anyway this this thread isn't about "do partners owe each other sex within a monogamous relationship?" (Cough they don't, no-one owes anyone sex for faithfulness, you don't like what you're getting you can fuck off not cheat).
The thread is about whether you owe your partner any and all sex acts they may fancy regardless of if you find them painful and uncomfortable, and they know that.
So if your wife wants to truss you up like Marcellus Wallace and bang you with a strap-on, you'd pretend to be in the mood for that if it's what gets her off (I'm presuming here this is something you wouldn't enjoy for its own sake)? And if you said you weren't into it she'd be entitled to cajole and sulk and eventually cheat on you with someone who shared her fetish?