Parsee already gain 1 hate mark if you are on a date with other girl and you encounter her.Sakuya with her trying to kill us everyday with Timestop knife throws.
Kaguya prolly going to start a yandere phase and kill others instead, Reimu will prolly nuke us, same as Marisa and a lot of others.
Maybe Parsee would break and become a full jealous wraith or smth etc etc.
If a "anger over cheating" is ever put in place she will most likely sic Yuugi at PC