Noun
serial monogamist (plural serial monogamists)
One who engages in serial monogamy.
I've always been a serial monogamist. Kristen Bell
I'm a serial monogamist. I'm not one of those people that can date loads of people at the same time, it's all too complicated. Daniel Radcliffe
I am definitely a serial monogamist. I can count on one hand the number of guys I've been with. Danica McKellar