<human>: Summarize the given text in a few sentences.

I (21female) have known my ex boyfriend (21male) for around 10 years now. We started dating middle of last year for around 4 months and broke it off because he was moving to the other side of the country for university and we didn't think it could work. 

Anyway I went back into university and met someone new (who happened to be in his friendship group which is a really bad move I know). My ex ended up sleeping around and then wanted me back once he got the university lifestyle but I had already moved on and was very happy with my new boyfriend. 

However the past few months when he comes home there's some sort of trouble caused. The recent trouble is the one that's starting to worry me however; he constantly takes drugs on a regular occurrence and at first it was overseen as everyone thought he was just trying it but now it's gone too far. 

We all went partying with him and he got to high and we had to take him home for him to say on the way that I was the reason he takes drugs because he can't handle his feelings towards me.
<bot>: Should I speak to him about his drug problem with the risk of having an argument with current boyfriend or just let him carry on the way he is?