If you are thinking it really is over, then I'd suggest thinking about snowmelt's advice to get yourself back on your feet.
It feels terrible to be displaced, but with all the drinking and crazy sounding things there -- I hardly see how you being ID'd as a second wife person of stability by some teen friend of the daughter's is tops for horrors! Some of that other stuff sounds more blearghy to me!
Their life sounds... messy. There's honest swing and dishonest swing and if you have already
been cheated on... well. That's a dealbreaker to me. Lies can't fly a polyship.
I am so sorry for your burden. It's not an easy one to bear.