Coerced consent isn't consent [1]; the fact that there are different levels of violence and pressure involved in some cases of coercion doesn't mean that the less-obvious levels are okay.
IMO in an ideal world there would never be any pressure or obligation associated with any interaction. But in the real world, "okay" must have a wide enough margin to include situations that aren't ideal but are limited in terms of harm caused and moral responsibility of participants. It can't be that I am a rape victim for not wanting to hurt my partners feelings by sexually rejecting them. Some pressure is surely okay.
Is not the same as
> to avoid a fight
or
> to stop them from nagging me
There is a subtle but important difference between 'having sex for reasons other than immediate desire' and 'pressured into having sex'.
So-called "duty sex" has been recognized as a complex topic where consent is concerned. Surely this is a continuum rather than yes/no. I can't go around calling an ex-girlfriend a rapist because she nagged me for sex now and then.