What a TW&T!!!
I sorta know how you feel mate. Me and the Mrs split after 14yrs together. Things were going wrong for a while with us, but when she told me she wanted to break up, well I was devastated
I am however over it now, although, I have been taken to the cleaners. I was messed up mate
She got the new A3 S-line, The house, and most of the stuff in the house. I had some cash in a trust fund, and also a share of my late mum house, so at the time I thought I was doing the right thing.
The best advice I can give you is, don't give anything away, and make sure you keep your house. Just give her and the ex-mate a wide birth.
Good luck Matey. You will get through it.