I am thinking perhaps you perceived your relationship with LO somewhat differently than how he perceived it? Like, maybe he didn't think it was the kind of relationship that could become a committed relationship, even though to you it seemed like it could be a committed relationship.
Creating a committed relationship between any two people requires the full consent of both people. If LO doesn't want to form this committed relationship, you have to try to respect his reasons and freewill. It's probably okay to keep talking to him about it up to a certain point; if talking about it starts upsetting him, then it's probably time to ease off.
It's not necessarily a fair situation, but, in life sometimes unfair happens. It's not like you can make LO's choice for him.
"Closed V's exist, right?"
Of course. I live in one myself. It's just that they're not right for everyone; maybe a closed V isn't right for LO? Only he can decide that.
It sounds like there is some uncertainty about what LO will decide. As long as there's uncertainty, and as long as he's okay with talking about it, then you can continue to talk about it, try to find out where is misgivings are, and see if they can be addressed.
Hope some of this helps.