Philosophical question about partnership?

There is no such thing as unconditional love (in my opinion) There is a line that he must not cross. My partner is not perfect. He has flaws, as do I. We are perfect together and I love his flaws, not just the qualities. If he were ill, incapacitated in anyway I would love him and support him as much as in health. If that illness were mental I would do the same. If he hurt my kids, thats another story. If he beat me, he is no longer the man I thought he was. If he cheated on me, he would not be the man I fell in love with. There are lines in every relationship that can not be crossed. Now the real problem I am having is considering whether, if he did any of these things due to mental illness and was not of sound mind when it happened. Honestly, I dont know. There is a point when self preservation kicks in with us all. Fight or flight. I will say that I could forgive anything he did to ME in those circumstances but where my kids are concerned, they come first and my duty is to protect them at ALL cost. The truth is that none of us can give the answer because no one knows until faced with the reality. I hope I can never answer this question with any real insight.