State of the art (sometimes cutting edge) refers to the highest level of general development, as of a device, technique, or scientific field achieved at a particular time. It also refers to such a level of development reached at any particular time as a result of the common methodologies employed at the time.
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.