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Boyfriend being a 5 star dic*

So guys this is a long one . And I know some people may see it as a petty thing but I just wanted to know if I’m correct here or not .
STORY TIME
so there’s 4 people involved in this story
Me 1
My boyfriend 2
My bestie 3
And her boyfriend 4
So 3 owns her own business making handmade accessories and sotmiees she drops off free ones sometimes for me in return that I post pics of myself in them on insta , influencer typa thing .
Anyway , her bf , 4 , has a reputation of cheating on her ( which she’s aware of ) and flirting with anything with a pulse , including me , in fact he’s sexually harassed me .(which she’s not aware of)
So obviously me and my boyfriend ,2, are not fond of him at all , and try to avoid social engagements with him at all costs , sometimes it’s hard for me as when I want to see 3 he is there .however I am civil with him just to remain friends with 3 and so there’s no bad vibes ect . My bf would love to smash his face in but I’ve begged him to remain calm as like I’ve said I don’t want any bad vibes between me and 3 .
Anyway this evening I was just chilling on my bed when I get a message off 4 saying “3 has asked me to drop off an accessory, I’m round the corner be there soon”.
So obviously this is the LAST thing that I want , being alone with him . So I said can you drop it off in the mail box ? But he didn’t see the message . So anyway I messaged 2 and said look just to let you know 4 is coming round to drop an accessory round on behalf of 3 , I had no idea he was coming until he was around the corner , I won’t let him in the house so please don’t be angry with me. So my boyfriend understandably is pis*ed off I’m going to have an encounter with him , which I understand considering the circumstances. However this is the part that’s annoyed me .
My bf defied to kick off at me and say stuff like “we’ll have fun with him then “ he also said “you could of said u were busy” he also said “you ACT like you don’t like him but you dont exacltly try your hardest to avoid him” . So basically he made it out to be all my fault and that I actually like having him around me and that it’s all an act ? I explained to him it’s not like i asked him to come round ? And he was already on his way anyway. Also it’s not like he was coming round for a brew ? It was simply to drop something off , I didn’t let him into the house either . Also I couldn’t of said sorry I don’t want you here , being as 3 would click that there is something up .
So guys who’s at fault here , and do you think I should be taking the blame and be made to feel I did something wrong ?