Bluesky there is no such thing as "obligatory sex". When I was 17 my boyfriend decided to exercise his right to "obligatory sex". He held me down and raped me. Rape. Not obligation. Rape.
I'm really sorry you had to go through that :-(
What happened to you is rape, not 'obligitory sex', no matter what he called it.
Its a far cry from someone not being hugely in the mood, but deciding to have sex because her husband is really in the mood, and she knows she'll enjoy it once it starts.
Coerced sex is rape. Sex that someone has been pressurized into (but still consents), isn't rape, but is pretty shitty unacceptable behaviour, and gives massive alarm bells.
Sex where you roll your eyes slightly and go 'go on then' isn't rape any more than your kids persuading you to buy them sweets when you hadn't wanted to, is theft.
Most people have probably had 'go one then' sex occasionally - especially when TTC, and it being on a schedule, or when work is really busy.
Anyway, I don't want to derail the thread, but in a couple of posts there has been a horrible undercurrent that if he asks for sex, he's nagging, and if he's nagging, he's a rapist. Ergo, the OP is a rapist, and I really don't see that is fair at all.