My wife has changed character completely and now wants to leave me?

We've been married 27 years. We have 2 daughters in their 20s, we share a mortgage & both work in the same company. I love her more than anything but the past 9 months have been complete hell. She's always been very warm and loving. But she has since became cold towards me and started putting me down for things like my health and the fact I'm 'boring' and don't have a social life. She joined the gym and goes every single day, sometimes for hours at a time - she has lost so much weight I barely recognize her. She sits on Facebook for hours daily and is always texting her friends. I hardly ever see her anymore. My daughters and I are convinced its a midlife crisis/pre-menopause situation. I've become severely depressed to the point where I was signed off from work for weeks and my wife didn't bat an eyelid. One minute she tells me she wants us to separate, and the next minute she acts like nothings wrong. I tell her how much this is affecting me but she turns it round and says I've been emotionally abusive for years. I don't know where this is coming from and I don't know what to do. She refuses to get help or counselling. Any advice?

Read more: My wife has changed character completely and now wants to leave me?