you've been took for a mug mate, but it doesnt mean you are one

Can she afford the mortgage?

Tell her you want to sell, she can buy it with her own mortgage but put it on the market.
Chance's are unless she's minted she wont get one, then either her and loverboy get one together(after a couple of month's he'll probably run a mile ) or she'll have to move somewhere else, back home or in with loverboy but again can you see him wanting that?
Make it hard for HER mate you've done fuck all wrong.