Ok I hate to bring this up but your reply simply makes no sense & why must people get married if they want open relationships?
So traditions, pure love or some other fairytale shits.
Just let MC make the same mistake as all his more experienced friends and get into trouble too.
This game is actually full of conjugal love. One of the MC's partners lives separately from her husband and both cheats. The other one cheats on him completely without any scruples, another married for money and power and in the end was glad when her husband died and immediately took his place. The other three started having sex with him to get rid of their "husband". Then we have one partner who was dragged off to a circus or something.
After all, even the MC is a cheater's bastard.
Like I said, true love story everywhere