i agree with all of the above comments, but also wanted to let you know that i know where you are coming from. ive done the same - with my axbf. He relapsed but continually denied and lied - but I started to miss him (although not too sure what exactly i missed) so I emailed him, I go through moments of deeply regreting and then being devastated that he didn't reply immediately. After the initial email I then really hoped he wouldn't reply, but of course he did, we have now exchanged a few emails - some of his so random and rambling he has to be drunk when sending them, one include a link to a video of a song - the words were pretty scathing and indicative of how he feels about me right now he was also a bit rude in some of them - although the trend in them is still all about him, what he's going through, how awful i am - yet I still replied back and still told him I loved him - which i do - but I don't want to the be the partner of an alcoholic.
So its easy to say and to know exactly what we should do, but sometimes our hearts get the better of us and we do something against our better judgement - whats done is done. I wish I hadn't emailed my ex because I am hurting all over again. I am sure in some respects you feel the same.
BUT things will get easier, these moments of weakness will get few and far between. We will all get there eventually.
Stay strong