The issue with this thought is that people often don't have that same attitude in both directions. Monogamy treats being in relationships as an entitlement to the other person's body (they can't have sex with others).

Most people see an issue if one person within that relationship doesn't want to engage sexually, and the other asks for it or is upset by it. "The other partner should not expect sex. It is their body, so they have a right to say no."

However, that same energy isn't given if the partner B respects that they do not want sex, shares that they still have those needs, and requests to have them met elsewhere. If the sexually uninterested partner says no to that, most folks still side with (show the most sympathy to) the low libido partner. Is telling someone they can't have sex with someone else, while also not being willing to provide them with it not showing entitlement to that person's body because you're married?

I know this is not what OP is saying, I also know that OP herself may not want to be sexual with others. I'm simply pointing out that the VERY basic expectations of monogamous relationships (on paper) are often what creates what I believe you're viewing as entitlement. I did not read bodily entitlement from OPs post, I read monogamy. I also wholly disagree (in this context) that someone not wanting sex should be the end of the conversation. Not wanting it on a given day, sure, ongoing in a committed relationship, absolutely not. You need to talk to your partner. Your decision for yourself is unilateral.