He also claims that he doesn't have to pay me a large part of his income,
I would expect that if a large part of his income comes from bonuses, then recent tax returns would be used. It was my understanding when we divorced that alimony could always be revisited - that is, if his income dropped precipitously in the future, he could go back to court and get them to reduce the amount he was paying me. So if he is arguing that last year was an unusually good year, perhaps you could include some specific provision to recalculate on a yearly basis or some such.
If he is hiding unreported cash from a business, then a forensic accountant may be needed.
If he moved out and furnished a new home, that money may not be recoverable - the minute he moved out you were "separated" and any money he gave you was more like child support/alimony even though not official. (If he wasn't giving you a penny, then you might have a good case about the house equity).
6 months to refi is not reasonable, btw. I had to have the ink dry on my divorce papers and a YEAR of cancelled alimony checks in order to finance my new home purchase after divorce. You should get at least a year.
As for your retirement being cashed out to buy the house originally - if you were married at the time, then all that means is that you definitely should be entitled to split whatever retirement assets exist now 50:50. Does he have pension/401k/IRAs?
And I understand that you want the house because payments will be cheaper than rent. Don't forget though that major expenses can go with houses (new roofs, water heaters, plumbing problems etc) and you don't want to put yourself in a position where you might lose the house and all your equity to foreclosure if you can't keep up. Just make sure you don't put all your financial eggs in that one basket.
