PMI is a cheating game with a sophisticated logic and points system involving each of the three principal girls and their potential (male) love/lust objects.
In essence, it allows you to defend your own relationship with your fiancee against the other men, by maintaining a good relationship with her, and/or pursue the other women in the game. But pursuing more than one girl at the same time might make maintaining your core relationship more difficult or limit how far you can progress with the other girls.
The game is character-driven, all of the characters have fairly unique personalities (although the two other men are assholes that primarily serve as antagonists) and the renders and body types chosen are quite distinctive.
Reminder: this is a cheating (and possible future NTR) game, so do not play it if you don't like this sort of thing. Betrayals by your fiancee are entirely avoidable, though, if you play your cards right -- this is not an involuntary NTR game.
I have never understood players who see a cheating or NTR tag, and then complain that the game has cheating or NTR in it! You are fairly warned.
But if you like this sort of thing, PMI looks to be one of the very best cheating games around, both in terms of the sophistication of its attempt to model relationship dynamics, and the appealing nature of the challenge.
It's early days, and I will revisit my rating at some point, but give this Dev a chance. I'm going to increase my support for him in Patreon -- he deserves it.