how to get over someone who lied to you about losing there v to you

its hard as from personal experience. i had a boyfriend who swore down on his families life and his own that he was a virgin (as i was a v and wanted to lose it to someone who cared about me and someone i could trust) however afterwards... he told me he had lost it to a girl in year 5 (i was in year 11 when i lost it to him) how do i get over him as when i finished him he goes sleeping around within a few hours from when i told him it was over from the amount of lies he told me.