Moseying over from god knows where...

we regret spending money on it in the first place, and somehow feel that keeping it (in penance?) will justify the earlier bad decision.

Dude, people have relationships like this all the time.  "Well, I spent all my time with [x], so I can't just give up [x]!"

[pain as a motivator]

Ayup.  I'm better about cleaning my cat's litterbox now that it's an open tray, rather than a covered one - I can see it.