Yeah, I have a few stalkers in my game too. It is weird the way you keep seeing the same sims hanging around certain other sims.
I say it's time for you to say goodbye to Marcus. Permanently.
The most annoying stalker in my game is Malcolm Landgraab. He will soon be meeting a watery end because he constantly calls Kyle Foreman wanting to hang out. Kyle is a teenager, and when Kyle's mom joins the conversation, Malcolm just stands around doing nothing looking stupid. How they ever got to be friends I do not know. I know he's just pixels, but he looks creepy standing there in the hallway (actually, he's probably watching the tv ;) ). I suppose I could say, oh, he's unhappy at home and is hanging out here wishing his own family was as affectionate and well adjusted as Kyle and his mom. I could do that. I even gave him a chance, but he ignores Kyle's mom, so there is no romance possible there. Instead I have decided that since Malcolm is a) evil, and b) unattractive even after a makeover, his wife is going to off him in their pool. (This whole thing is actually an excuse - I don't like Malcolm)