Sim's can't ask other sims to be boyfriend/girlfriend

my sim cannot ask anyone to be her boyfriend or girlfriend, even when they have full friendship and romance bars. another couple in a different save who are engaged cannot get married. i have tried removing all mods + CC and repaired my game but nothing worked. it only works when i make her forget all relationships using MC control center and then cheat the relationships back up. but i don't want her to have to forget all her relationships for it to work