Leave the past in the past, or let it back in?

Been texting my ex a lot recently and don't know if I should meet up with him or let bygones be bygones. We went out for 2 years and have been broken up for 2. I broke up with him and there was no contact for over a year initially which was fair enough on his part.

We met up for last December as he was back home for Christmas, he'd text me out of the blue to see how i was and I was delighted to hear from him. I hoped he would have changed and matured a bit as I always loved him, he just overdid the drinking and stoner thing which became too big a problem for me and was the reason i had to finish with him.

Meeting up was good, chatted for hours, had a great laugh. But then he got hammered and the old him reappeared...I ended up so disappointed with the night, way more upset than I thought I would in that i never thought i'd get upset over him again. It nearly felt like the break up all over again. I suppose I thought his problems were something he'd grow out of but there was no sign of that!

We'd no contact since, until two months ago I got a text from him and we've been chatting via text a lot - friendly and light hearted, nothing too serious but it turns out we're both going to the same event at end of July and he wants to meet up. Just don't know whether it's worth it, would i be better off forgetting him altogether.

I always think very fondly of him, i've gone out with 2 guys since breaking up with him and they were fun while they lasted but nothing has come close to how I felt when things were good between me and the ex. I never really missed either of them! Even away travelling all last year my ex would be on my mind a lot (the other guys weren't!).

In my head I am excited but nervous about meeting up. There's a slight case of rose tinted glasses in my case when thinking about the old days, and the texting just reminds of the reasons why i will probably always love him. I'm just afraid i'll build it up in my head, meet him, he'll be wasted and I'll just be upset again. On the other hand, I would love to see him and have the craic like we used to and just see can we hang out and get on well as friends - and if something happens again in the future then great.

Should I go and just have fun with the gang I'm going with and not get in touch or reply to him, or should I go and see if there is still something there with us? I know this all sounds quite trivial, but it's on my mind since I heard from him and would appreciate some advice.

Thanks!