Married to a pathological liar

I’m just coming to terms with the fact that I’ve been married to a pathological liar. I think I’ve always known he was a liar because of the small things I noticed he lies about, but I never thought it was that bad until now. I witnessed him lying to his family and friends and when confronted he denies it and continue to lie. Due to this I started thinking if he can lie to his family so easily then he probably lies to me all the time. And also his family has said they think he’s bipolar and a pathological liar and always have been. I found out about some things he’s done and I confronted him about it and he continued to lie. There was even proof and he still kept lying after seeing the proof and knowing that I now know the truth. I was in disbelief and a little amazed by his reaction and how easy it is for him to lie with no care or just a little guilt. He shows no remorse at all and even tried to convince me that I was making things up and it wasn’t him that said or did the things I’m talking to him about. We have a child together and I’m currently pregnant with another on the way. Due to certain things I’ve seen him go through and things he’s told me when drunk or feeling sad, I’m worried that his lying habits is stemming from some kind of mental illness like a personality disorder or something else. I’m also worried about how this might affect the kids growing up. I’m very unhappy and feel I’ve given my all to this marriage and tried everything to make it work. He doesn’t want to get help or believes he needs help, therefore there’s nothing else I can do. So for the sake of my happiness and mental health I will be getting a divorce. I’ve been crying constantly and I’m trying my best to stop because I know it can affect the baby in the womb but I can’t seem to stop. I’m really scared of how this all will affect my children and don’t know what else to do to make sure his bad habits doesn’t affect them.