Illich (noun) is a term that can be applied to someone who; can't finish or handle their piss, stingy or unnecessarily uptight with money, getting the boys in an unwinnable fight and/or arrested, or embarrassingly bad at spading the ladies.
The phrase is applicable across a range of situations and tones and rolls of the tongue nicely
Someone who jumps from one relationship immediately into another one.
Serial monogamists can not stand to be alone and often suffer from vast commitment and insecurity issues.
Because they jump into relationships immediately after the previous one has ended, serial monogamists typically don't take the time to reflect on their behavior or why their previous relationships failed; thus, they end up making the same relationship mistakes over and over again.
Person 1: Damn, Dustin already has a new girlfriend?! It's only been two weeks since he broke up with his fiance! I think he's a sociopath.