I agree with Treasur's recommendation for Out of the Fog website. No matter what it is you are dealing with, this site offers language for what you are witnessing and strategies for interacting (or maintaining distance) in these situations.
However, one thing I strongly disagree with on this forum is the advice that it doesn't matter what your spouse has. If your spouse has a mental illness that can be diagnosed, and you share young children, I think it is imperative that you continue to seek out support until you find someone who will listen.
Clues that your spouse may be suffering from a mental illness or biophysical event include:
• Recent changes to medication.
• Family history of mental illness.
• Radical change to personality, spending habits, and behavior.
• Other physical symptoms, such as new migraines, flat/emotionless expression.
• Sudden loss of empathy.
• Loss of emotional attachment to pets, home, children etc.
Some of these are couched in different terms on this site, but they are not the only way to describe them, and using the correct terminology may make the difference in a doctor/lawyer/child therapist listening to you and helping you to protect your children and yourself.
Barring any of these, and an honest assessment of your spouse's behavior throughout the marriage, may reveal your spouse has always had a personality disorder. In this case, I think it is really important to rely on advice for dealing with disordered people to avoid further traumatizing yourself. I would also specifically seek out a therapist with training in personality disorders.
I feel worried that at times people will engage in arguments about diagnosing on this site as if we are all dealing with the same thing. It is very likely we aren't. All to say, use this site to get information, but I would caution anyone from taking any comment as the final word or best advice, even. Each circumstance is different.
If someone tells you on this site that your spouse does not have a mental illness or does not have a personality disorder, or not to seek help, they are being irresponsible in my opinion. Try to rely on what you know of family history, your memories of your spouse, and what you are directly observing. Trust your own perceptions first and foremost.