Retroactive Jealously

Hi All please help

So me and my boyfriend have been together for about a year know, on and off through school but I have always been really into him. Anyway I was in a different relationship about 2 years back and my best friend and my boyfriend (wernt dating at the time) started to snap, blah blah she briefly told me about it and I told her I wasn't interested and they ended up hooking up.

They both actively hid it from me the night it happened and then she told me about it a few days later. Obviously I shouldn't have cared and I told her I didn't want to know about it and her and my boyfriend decided to cut things off and just made it a one time thing. Anyway about a year later me and him got together (me and my ex broke up) and I have just been really struggling with the jealously. Me and my best friend kind of speak but it's been more common now but after we hang out I just feel like utter *** and jealous. My boyfriend is so amazing and doesn't deserve to know any of this and how I feel because I know he can't change it but it is eating at me and making me so unhappy.

I don't struggle with the jealously with his ex’s, it is mainly his previous hookups and obvi the one with my friend

I'm so worried it will ruin our relationship because if it didn't exist it would be PERFECT

I tried talking about it briefly( just told him I was getting in my head and getting really jealous and he didn’t say much at all just told me it was okay and that I can feel like this but nothing else) he reassured me that we will make it past it but I feel like I’m so own my own

any tips please thank you so much