E.,
What was your hope when you got involved with this man? To move in or to marry him?
I can tell you this-- I think that the man you are with is not going to ever marry you. He might love having you around, this might be a fun and very easy relationship for him because hey, you don't have the baggage of kids, but no, I don't think that he's committed to a long term relationship with you.
When my husband and I first met (platonic, I should add) we were both going through the ends of our marriages with our respectful spouses. Ten months later, we started dating. While we both were already separated from our exes, I had already filed for divorce from my ex and he quick-time got his divorce taken care of. I wasn't going to stick around if they were going to stay terminally 'in limbo'--separated but not divorced-- and he knew that.
HAD I stuck around while he dragged his feet, well, that would have shown him that I was willing to wait around indefinitely, that I didn't have needs or desires of my own to be in a long-term, fully committed relationship. We didn't marry for a long time-- we'd been together for 8 years and had our son almost 2 years prior-- but I knew he was was FULLY committed. There was absolutely no ambiguity and you know, my husband wouldn't have wanted there to be any, for both our sakes.
I tell you all this because I don't think it's necessarily about anyone putting a ring on anyone else, but all about this sort of ambiguity.
If my girlfriend were in the situation you describe, I'd tell her that she had some options:
You could ask him to go to couples counseling with you, because you wanted to better understand what was happening and want him to understand why this is so concerning for you.
You could tell him "no way, buster, am I content to be your faceless girlfriend who doesn't know your family." While families are weird and a beau may be a bit hesitant to introduce a new love to family, usually someone who has intentions of a long-term relationship with someone is proud to be with them and WANTS to introduce these important people to each other. (Unless there is an estrangement issue which previously exists, which is understandable, but that's not the case with you.)
Personally, I think the writing is on the wall. He doesn't want to make an effort to even *translate* for you. Sweetie, that right there says it all. He likes you if he doesn't really have to make an effort. Chances are, if he goes off and tells you the truth, you might dump him and if it doesn't work out between he and the ex, he's back to square one, alone. In this way that he is proposing now, reassuring you that while something looks odd, everything is fine--- he pushes all of the risk in the relationship onto you. If they do reconnect, you are the one who gets blindsided. And if they don't, you might end up wondering if he's still really wanting to be with you out of sincere love or just convenience.
I hope you listen hard to your heart. I think you know the answer already.