I've seen the "ask to just be friends" interaction before. I looked under friendly and romantic socials, but this time, it didn't seem to be there --- and I looked very, very carefully. I had a big party at a generic lot, and that's when I had this problem.
Scoed --- I don't have the Vampire GP because I don't like spooky/scary stuff. Thanks anyway!
Edit: I got the romance bar to have a small amount of red by using that cheat, and so, it's fine for now. However, If I can't get rid of the romance bar, then, I will have to deal with it, I guess by having the son-in-law insult the mother-in-law --- only when necessary from time-to-time because I don't want to beat her up, or worse, "delete" her.