how to stop being jealous?

my boyfriend loves me. it’s so clear and he’s not afraid to show me off and he’s very loving around friends and family and most of his attention goes towards me. i know he loves me. but he’s also very social and friendly towards other people, including my friends. and i know that they wouldn’t do that to me. but one day my friend reluctantly told me that one night he called her hot. and when i asked him about it he said that he was buzzed with his friends and he didn’t mean it. also i’m bisexual so he thinks its okay to hit on other girls because i may also find them attractive. it makes me jealous and self conscious. i told him and he said he wouldn’t but he still does. when i’m with my friends he will talk to them way more than me and that’s fine. i just get really really jealous. and usually i turn that into quietness. i don’t ignore him or give him the silent treatment, i’m just quiet. and recently, we had a red heart next to each others name for a couple months on snapchat cause we were our best friends on snap or something and it went away today. i asked who replaced me and it was my friend who he called hot. i felt the jealousy clawing away at my throat and chest. i know it’s irrational and i try my beat to not let it show, how do i fix it???? how do i become less insecure in my relationship???