honeymoon hopper

A person who loves the initial rush of endorphins from the early dating phase. They use their charm and flattery and gestures to make you feel special, but when a real moment comes along where the idealised fantasy they have of you starts to crack, they lose interest and move onto the next one, and the cycle continues.

He honeymoon-hopped me

I would stay clear of her, I heard she's a honeymoon hopper