Mid-Life Crisis / Betrayed or Completely Selfish?
Question: Is it still considered to be a mid-life crisis when you find out that your ex was lying to you for 6 months while he was sleeping with new girlfriend 10 years younger who I believe was married twice and now separated or divorced "I am not sure"? How long will a relationship like this last and has he truly found happiness or is his penis thinking for him?
I don't know the answers to your questions, as I don't know how old he is, what your married life has been like, or anything else about him.
As to whether he has truly found happiness - only time will tell, and even then, only he will know.
What are you doing in your life to find happiness? That is something you can do something about.