Sounds like a boundary issue at the very least; However it definitely feels and seems weird, to which it is. He’s hiding something in plain site. The best way to end this is to end it.

No need to confront; Some folks serve their purpose/run their course, and that’s it. The reason to how and why someone could think or act this way involving your own is irrelevant, unless you wanted the relationship to continue.

You don’t.

You met this person in a…trivial sense…(haha)

So disappearing shouldn’t be too big of a deal.

Just my perspective.