<human>: So basically I am currently dating my boyfriend (21male) of almost a year and very much in love with him. However he is my exes best mate and I already know it's an awful situation before anyone reminds me. 

But they were best friends ever since they were small and my ex (21male) and me have been friends for over 10 years but only started dating briefly last year before he found out he was going to university at the other side of the country. When he left he broke up with me which I was devastated and he ended up sleeping around almost straight away which made me realise we weren't went to be together. Me and his best mate were good friends already and started to hang out much more and ended up getting with each other a month after my ex moved away. Every time my ex came back he caused trouble and kept saying how much he wanted to get back with me.

After a year on we both apologised and now my boyfriend is back mates with my ex (which I wanted because now he has all his mates back), but now my ex takes heavy drugs and we all went out for a night out last weekend and ended up looking after him with me and my boyfriend taking my ex home. To top the night off in the taxi he said he takes drugs because he loves me and can't stand the thought of me being with my boyfriend.

Condense the text into a few key points
<bot>: I am worried about my drug taking ex and wondered if I should talk to him if it's me causing him to take drugs or to leave him to his own actions?