Lost and Confused

So I have had epilepsy since I was six months old. I am now in my thirties and I have been in a relationship for the past eight years and we have two kids together, I recently had a seizure that made me lose my memory and made me not be in love with the man I have been with. Before the seizure I got invited to an old friends birthday party and I started talking with this old friend again. At the party we each found out that when we were in grade school we each had a crush on each other and that he still has a crush on me till this day. After that I started acting differently and made plans to hang out with this old friend. Who has been looking to move to Colorado since the end of September.    During my seizure I kept getting flash backs. I could not tell if I was with my kids dad at home or in the emergency room with my old friend. The next day after the seizure I started to lose my memory and I ran to the familiar which just happened to be my old friend along with someone else and even though he won't admit it I think it made my kids dad jealous. At the time my kids dad and I had an open relationship. The only rule we had was no kissing the other person. I made plans to see this old friend before I had my seizure and I told him about all this and he wanted me to feel what it was like to be with a man who treats a woman right. So I did end up kissing him. I chose to be honest and tell my kids dad the truth and that I kissed my old friend. After he found out that I did not even feel bad about breaking the rules and feel sorry for doing it he broke up with me then tried to get back together with me a few minutes later. He is  saying I cheated on him with my old friend. Then he gave me an ultimatieum. Either I stay friends with this other guy or I be with him.  I have been told that my kids dad is not the greatest guy. He has a temper on him and he has no problem sleeping with women he is not in love with. He has physically abused me.  I have been told that because we have kids together we should stay together, but I have also been told that we don't have to stay together for the kids. If I chose to leave I am afraid to take the kids with me and live on my own because of my epilepsy. I have a friend that would be willing to take me in but has no room for my kids. It does not help that my dad is saying that if I left without my kids I would be leaving them. Is he right? I don't know what to do anymore. I am unhappy but don't want to leave my kids. Lost and Confused