I’m 28F and he’s 29M

Recently we had an issue and were discussing the possibility and how comfortable I would be with the relationship being open on his side. What are the men’s thoughts on this?

I’m considering it because I’d like to believe I have a decent understanding of men, I have a lot of male friends and we’re surrounded by male family members from childhood into adulthood. Most or a lot of men are interested in multiple partners even if they love their current partner. Many claim “it’s just sex” of “it’s just a vice”. My father has had a few instances where he’s cheated on my mother, so I think that’s why I’m even considering it