People argue about sex using the word "need."
"I need sex."
"Sex is not a need."
"If you loved me, you would care about my needs."
The language quickly becomes moral.
A more useful approach is to separate biological survival, emotional importance, relationship expectation and bodily consent.
Sex is not owed
No relationship status creates automatic access to another person's body.
Marriage does not erase consent.
Commitment does not make refusal a breach of ownership.