If he didn't, then the argument would be "oh he's too lazy to do anything with all that land he bought. What a deadbeat!" He's damned either way. Seeing all the work he's putting in to give Amy exactly the wedding she wants, I think he's one awesome ex-husband. Not that she shows a lot of appreciation. Her attitude is one of entitlement, as if that's how it should be, when it's not.
When has Amy ever built a cabin?