Seems to me he was sick of living at the Extended Stay and he must have figured all it takes to move into a nice place with a golf course in the back yard was an engagement ring. He walks in the door and finds another dude and looses his mind. After all he probably just blew $100 bucks on a ring.
Either way hotel surveillance will show him with another chick at the hotel (pre incident), and unless he has a receipt for the ring, the prosecutor will be able to prove the engagement ring is a ruse and also cement the criminal trespassing charge too.
Dude is fucked either way.
Wonder when we find out who his other woman is. The fact that she was still with him after the incident (The Big Mack Attack) goes to show some women will never learn. "I'm sure I will be the one to tame this wild beast."