Does your partner or former partner cheat financially?

I'm divorced.  Ex apparently hasn't changed his address yet, even though the divorce was finalized in May 2016 and he had already been living with his parents nearly full time for three years by then.  Yesterday, for the third time, mail arrived from the state department of revenue. It was clear from the envelope that ex hasn't been paying his state income taxes.  It's not for lack of money.  I think he doesn't pay taxes for a combination of reasons: partly from the ADHD and partly because he thinks he's poor (he's not) and is happy to cheat people out of money when he can easily do so.  

How is your partner or ex with money?