I almost guarantee this is a shelter / disaster prep, the "inherited property" thing is what is the giveaway.

All of a sudden he has a "playground", maybe some cheap property that doesn't have a great use or value otherwise. Those become nice to have for dude toys and dude projects.

Girlfriend of course has multiple agendas that she didn't discuss with him and doesn't like any activity outside of those, which is garden variety manipulative partner stuff.