Marry her!
That'll show her what's up!
The main issue is not her now, but you buddy - find out why the this happened - so it won't happen again:
( "... I put her in a 300k house, 30k Lexus to drive to school back and forth..." )
Hang in there and remember the crazy ones prey on your loins faster than a mongoose on a cobra. It's their lifeblood. She's just passing on her dysfunction and sex is her only collateral and you were a willing participant. Take that car and floor it. Thank god you're learning this now and not like when you're 50 and wearing a gold chain and driving a red convertible in West LA!
Peace