Other girls are attractive

Boyfriend of 3 years only in past 2 months has started seeing girls on tiktok and searching them up on other social medias, took him 2 hours to get out of him why he does it he then replied after me asking so so much why he does it with “there a bit attractive” I said there’s a difference between seeing someone and thinking oh there attractive but the fact he went out of his way to go look for more . I don’t know what to do and it also makes me feel shit about myself that I’m not good enough