Mate I’m going through the same thing you are right now, just with an infant child instead of adult kids. I had a complete mental breakdown after a sever bought of bipolar depression, three suicide attempts and a dissociative episode that resulted in me writing of two cars. As a result, I haven’t seen my baby in 3.5 months. I’m telling you this because I don’t want what I say next to sound like a bunch of crap you can’t relate to.
It sounds cliche but taking things one day at a time is the best thing you can do. The best piece of advice I can give you is to find days and weeks where you don’t fight in the mud with your wife and kids, her family or yours. Give yourself a chance to find peace.
Work on yourself, see a therapist, exercise, read, get right with God, rise above and focus on being a better person. Go to the doctor and see what they can do for your depression/anxiety - stop fighting your battles along and without help.
If you’re drinking or taking drugs, stop doing that. If you can’t stop, go and get some help with it and start changing the parts of your story that you can control.
In other words, do the things you can control spirituality, physically and mentally. Look after yourself as a priority, love yourself, be kind to yourself. Crap happens, and impossible situations can turn around in time.
The legal process is slow. It’ll be two years before you get a ruling in court, so take your time and don’t catastrophise how you’re going to pay for things. I know, lawyers suck you dry, but it’s just money. Focus on your health.
If your kids are grown up and it’s just the house to split, accept the fact you’re going to be down a bit of cash, you’ll need time to show your kids how strong their Dad is, but you will live to fight another day. Accept your failings, forgive yourself and be encouraged to build yourself back stronger.
My shit show is turning itself around despite the absolute chaos I found myself going through. I’m with you buddy, we can do this. I have faith in you and what you can achieve.