Hi Broski,
Sorry to hear of your situation. Not pleasant.
Maintenance - Difficult one. Depends on a lot of factors. Ages, income levels, earning potential, size of asset pot, need etc. With negative equity in house, big earnings discrepancy, it is a possibility.
The house is a marital asset (or liability it seems). Normmal procedure for ten year marrige would be a 50% split of assets and liabilites. So in the event that your wife agrees to the sale of the house, the shortfall would be split 50:50. The house could be ordered to be sold in ancillary relief proceedings once a
divorce petition is served, but the question is, would your wife be able to take on the mortgage herself? As co-mortgagees, you have a joint and several liability for the mortgage. If you stopped paying, they would come after both of you for the arrears and you could get yourself a bad credit rating. The mortgage compnay would only let you off the mortgage if your wife had sufficient income to sustain the mortgage.
Adultery - Yes, your wife could cross petition you on adultery. Absolutely pointless, and very expensive to do this. If the marriage is over, it is over.
I appreciate that things are not good between you at the moment, but you need to agree how the house will be dealt with, and how the divorce will be dealt with. Divorce is no-blame. It makes no difference at all to the financial settlement as to who divorces who and on what grounds.
Yes, your wife could name the co-respondent. Very inflammatory, and again pretty pointless. Only you, she, you respective legal counsel, the court staff and the Judge who hears the petition will see it.
Hope it helps,
Mike