This really is a tricky subject for a lot of people. And backgrounds/gender politics do inform a lot of it, unfortunately. In same sex relationships, it is pretty normal for people to actively want sex, but feel guilty for it due to years of being told their desires are wrong/immoral. In those cases, it is pretty common for one partner to need to work with the other on accepting that their desires are good and normal. In a heterosexual relationship, this type of persuasion might be seen as coercive.
If a person in a relationship wants more sex than they are getting, it is probably good for both parties to sit down and talk about how they can each get their needs met. No partner ever owes the other partner sex, and if a previously sexually fulfilling relationship suddenly is not, there might be other factors in play. Trust issues, stress, medical problems, etc. If the other partner actively wants to get to a place where they are mire comfortable with sex, there are therapies and at-hime exercuses to try.
In your specific case, there are a lot of unknowns. If the other person had some sort of power over you, such as a boss, teacher, caseworker, etc, then it would be sexual harassment. Because the person would know in advance that you would be likely to feel mervous about turning them down.
If the person had no power over you, and you were on equal footing, it would depend on whether you communicated your discomfort. If you did, and the other person kept pushing until you said yes, that is a type of assault (though, depending on the laws where you live, it might not be something uou can prosecute). If you did not clearly express discomfort, the other person would have no way of knowing that you didn’t actually want to have sex.
Simply asking someone if they want to have sex is not assault unless the person does not accept a refusal. I cannot tell you how many times I have had someone on a dating site message me with something like “hey would you like to do [whatever sex act they had in mind] tonight with me?” And I would say no, and they would be like “okay then, bye.” I have had similar interactions at bars and parties. It is not assault for someone to express an interest in you. People with a history of having boundaries violated might have difficulty saying no, but that does not mean they no longer have the ability.
I think the mindset of “any guy who hits on you is abusing you because you might not feel comfortable saying no” hurts survivors more than it helps, because it keeps them in a mindset of having no agency or power to assert their own boundaries.