Look, coming up with a story in your own head reading the tags instead of playing the game is just pure ignorance. That being said I have yet to see a game where prostitution doesn't just mean that your love interest fucks around.
I have a pretty lax stance to multiple partners, and I don't scream NTR at every occasion I get. My stance is simple: I don't care to hear about a partner's former sex life (I don't care how many they've had, couldn't care less if they aren't virgins, I just don't want to hear about their past sexual experience), I don't care about fly on the wall scenes where my character isn't present and NPCs are fucking, and I don't care to play a guy who knowingly accepts the role of just +1 dick among several other dicks a person of interest happens to be riding concurrently... prostitution ALWAYS is one of these 3.
So while being presumptuous is bad, it's quite obvious what certain tags can and can not stand for.
EDIT:
So I've started playing the game, and shocker, I wasn't wrong, but I only called quits a bit later, when the second woman (out of 3 who are added to character profiles so I assume are potential love interests) came around who fucks other guys. No, just no. People with a cuckold fetish will have a blast with this game, I'm not one of them.