<human>: My boyfriend and I have been dating for about a year and a half now. In the beginning, I felt like I put with with a lot of things that made me uncomfortable but after about 6 months the relationship started to get better. 
He pretty much used to smoke weed all day with his friend and do nothing else. Plus he used to be a drug dealer. He's had a history of using quite a few of hard drugs as well, but that was before we started dating. 
What bothers me the most is he did LSD while we were dating and he knew how I felt about hard drugs and still did it with his friends. 
The fact that he used to be around such a bad crowd at a young age lead him to do make a lot of stupid things. 
One time during the relationship, he even ditched me to hang out one of his ex-girlfriends. He apparently used to still talk to a lot of them behind my back . 

A year and a half later he is a completely changed person, and he tells me im the one he wants to marry and be with for the rest of his life, and I could see it. He dropped all his bad friends, stopped doing drugs and regrets everything from his past. 

I guess what my problem is, is that he is already experienced and I'm having doubts if I want to spend the rest of my life with someone if I haven't even explored other options myself (he's my first for sex and he's already many partners). The fact that he used to do a lot of heavy drugs and sell drugs at such a young age makes me wonder if this is the person I want to be with. I said he has changed a lot, but that happened very quickly, I'm afraid he could change right back into his old self.

Condense the text into a few key points
<bot>: boyfriend used to be into heavy drugs, sell and smoke pot all day, continued to talk and hang out with his ex behind my back and get mad at me for even being upset over it.