Technically, we are free to date other people since he does not want to commit, but in reality neither of us wants to date other people, and so we don't. I would actually be okay with him dating someone else. I know what I mean to him and wouldn't be jealous. But he refuses and I think HE would not be on board with me dating someone else.
With strangers, he will sometimes accept the term "boyfriend" because it's the easy way out, but mostly he will say things like "she's with me" or "we're together" or fumble for explanations, which is very awkward.
The thing with my ex is pretty complicated but yes, G. knows about it and says he is okay with me still loving him. He knows that it's very hard to just stop loving someone whom you've spent a decade with. I've been very open and straightforward about it with G. It's not so much that I'm still in love with my ex and would like to rekindle the relationship - that ship has sailed. I was the one to break up and divorce him, and for good reason. I would never want to go back to him, but we shared some good years and memories and I am still fond of him despite what happened.
G. says his reluctance to put a name on it doesn't have anything to do with my ex, but for some reason I'm not so sure. I feel like he is just a little bit insecure about that. He's joked that I'd ditch him the first chance I got if my ex showed up with my favorite sweets and apologised, and that didn't sit well with me. He was just making a joke about how much I love sweets, but I couldn't help but feel that there was something more at play there. When talking about it though, he says of course he knows that I won't go back to my ex husband.

Well. I will ask "Hey, can we talk about how we define our relationship? It's very frustrating to me to not know if we are together or not."
G: "Of course we are together. Why do we have to put a label on it?"
Me: "I know you don't like expectations, but if we put a label on what we are, I'd be less concerned about just being a toy to you. It makes me insecure to not know how you see me."
G: "I'm sorry. I just really don't like labels. Labels create expectations and expectations ruin all the good things. You know how much I love you, you don't have to be insecure just because I don't want to give our relationship a definition. Is there anything I can do to ease your worries?"
Me: "Yes. Just say I'm your girlfriend next time somebody asks."
G: "But boyfriend/girlfriend sounds so immature."
Me: "Then pick another term, one that resonates more with you?"
G: "Like what, partner?"
Me: "Sure, that works."
G: *introduces me as his "partner in crime" the next chance he gets.*

He tells his friends that he doesn't know what we are. They've been making assumptions and he's actually been getting quite annoyed at them, but really, what are they supposed to think? To everyone, it looks like we're a couple, so they'll call us that.

That's what I thought at first, but no, he gets offended when I imply that. Also in every other way he is NOT acting casual. He's totally smitten with me and it shows. His sisters have actually taken me aside and asked what I'm doing to make him that happy all the time, they'd like to know the secret ... lol. His friends are telling me how good I am for him and how glad they are that I'm with him. His parents died not so long ago and he's had a hard time coping with it. He's been pretty withdrawn the previous months and everyone was concerned about it. But since we got together, he is much more his old self again. I don't want to force anything. If he just wants a casual fling, okay, but he swears up and down he doesn't and besides the definition problem, he isn't acting like it either.

I do get that y'all don't know what's going on in his mind, only he can tell me that. Thank you for taking the time to read all this and to help out It means a lot to me. It's really hard to talk about this with anyone else.