A confident explanation one would give when asked how much longer a task may take even though in reality the person has no clue how long it might actually take.
When we asked our mechanic how long until our car would be ready he replied "soonatarily".
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.