<human>: So a little history. We have been dating for a year and a half and have known eachother for about 3. We worked in the same building but for different companies but would see eachother everyday. I always thought he was attractive but he was in a relationship so I stayed my distance. I found out his ex had given him back the engagement ring, so I asked him out for drinks since I had cut off the guy I was talking to a few days earlier. Long story short, a new relationship bloomed. 

Fast forward: we've had our little disagreements here and there but deal with everything on a mature level. We get along very well, worked out the idea of not having kids, (I'm totally childfree he wanted them in the beginning but he's agreed they are not for him either) and share common, as well as, different interests. When we first got together I told him that I have a certain rule. If after we've been dating for 2 years and I don't have a ring ony finger, I will end the relationship. Before I start getting called names, let me explain. I have witnessed many friends of the family and my close friends get strung along in long term relationships just for the other person to leave them. I don't want that happening to me. 

We've talked about marriage in the past, and he says he's up for it. But I just can't shake the feeling that he's just riding out the next 6 months to just end it. What should I do?

Can you give me the gist of the text in a nutshell?
<bot>: boyfriend of 1.5 years knows my limit is 2 years before walking away if there isn't an engagement. Need advice