I was afraid of that when you mentioned that you had deleted a sim. It's nothing I've ever messed with , but I believe the only safe way to delete them is through SimPe and you need to erase memories and lots of other things from the sim you are deleting and all those that they have ever met. Otherwise , according to Pescado, the neighborhood goes boom. It's much easier and safer to just "off" them in some fashion. I use a no jealousy hack unless married or engaged to avoid the angry dater syndrome you initially described. I'm building a new hood and plunking lots of Criquette's awesome neighborhhood deco, from which I need a break. So I'll go poke around at MATY for a bit and if I find anything pertinent, I'll update this post with a link. Good luck!
Might help...
http://www.moreawesomethanyou.com/smf/index.php/topic,17432.0.html... snag the lot debugger and instructions while you are there, good luck!