People will give you different answers depending on how they see and experience sex.
....For some - and many women will be in this category - sex is an emotional and sexual connection. So - for those people love and sex are connected in a very strong way. They need emotional connection to have sex,
....For other - sex can be with an emotional connection OR without. I think it's rarer in women. And this is where the differences in opinions will come from. Sex without emotional connection is possible for these people. And they can love one person and have sex with another person. People in the above group can't relate to this.
I am not a man - before people start accusing me of that. I don't necessarily need an emotional connection to have sex. I think I did when I was younger. But with time - kids; experiences with different stages of relationships; losing my libido post babies and regaining it; getting older - things changed.
Maybe for women it's related to fertility and our stages in life. I don't know.
I do know that a lot of things seemed more black/white when I was younger. Less so now.