crazy ex! need advice!(long)

so i’m 15. just recently had my birthday. about a year and a half ago, my ex and i broke up. he got drunk and broke up with me. a lot went down. harsh words were said by him. i was all around heartbroken. for the next two months, i was depressed. we were on and off talking but in the end, the police were called due to harassment (he texted my mom and said some very rude things). when i began dating my current boyfriend (we’ve been together for almost a year and a half), i was still talking to my ex. it’s one of my biggest regrets and i wish i would’ve just dropped him. my current boyfriend found out and i dropped my ex finally. it was hard letting go, but it was for the better. about a month ago, someone texted me from i number that i wasn’t familiar with. he started dropping hints that it was my ex but when i asked why he was reaching out to me after all this time, he asked who i thought he was and was being annoying, so i just blocked him. i never told my boyfriend about this because he didn’t have his phone at the time and i didn’t think it was a big deal because nothing really happened. two night ago, he messaged my boyfriend. he was saying “i’d first like to congratulate you for getting out of that horrible situation.” first of all, that sounds nothing like my ex. second, he was trying to tell my boyfriend that i said him and i broke up so that i could now talk to my ex. my boyfriend didn’t believe it whatsoever because he was illiterate and that isn’t me at all. we also didn’t break up. (my ex is kinda dumb). my boyfriend replied with saying that he’s dumb and he’s going to beat him up (my ex has caused problems before and it’s getting to a creepy stage. my boyfriend was going to fight him before but didn’t want trouble). i’d be ok with my boyfriend fighting him because in my opinion, he deserves it. i know fighting isn’t the answer, but i can’t stop my boyfriend. i’m just afraid my ex will bring a knife or something and someone will get hurt. if they do fight, i’m gonna go and surprise my boyfriend there even though it may cause problems (because i haven’t seen my ex in the longest time and he might do something). my ex gives me major anxiety when he texts me randomly or creepily like this (he put me through A LOT) and just the thought of him makes me mad. i didn’t tell my mom about any of this because i’m afraid she’ll make a big deal about this. if i think of any details to add, i will. please give me advice! what should i do? should i tell my boyfriend about the other messages? it’s kinda getting really creepy and sometimes i can’t sleep. please comment! thank you!