have a roving eye
US /hæv ə ˈroʊvɪŋ aɪ/
UK /hæv ə ˈroʊvɪŋ aɪ/

1.
avere un occhio vagante, essere un donnaiolo
to be someone who is always looking at other people and is often unfaithful in a relationship
:
•
He can't be trusted; he always seems to have a roving eye.
Non ci si può fidare di lui; sembra sempre avere un occhio vagante.
•
Despite being married, he still has a roving eye.
Nonostante sia sposato, ha ancora un occhio vagante.