It would be cruel of you to divorce over your own child. Imagine what it would be like for them, I had similar issues with my parents, being not that bright. You have a duty to your child I think, the end of selfishness comes when you make that leap.
Actually, the strained relationships tend to hurt kids more than the divorces do. I've experienced my mother divorcing two times, once at the age of 5, the other at the age of 17. I am not emotionally scarred from either instance.
In fact, the first divorce was over the fact that my mother's first husband was beating me, so I'd hardly call that a detriment to me for her to leave him. So, yes, they divorced over me. LizaM isn't getting a divorce over her child, however, it's other issues.
For the second, there was nonstop arguing, and her husband was being unfaithful. Once again, life IMPROVED after the divorce, since the emotional environment was so toxic prior to it.
I am autistic, so I suffer from sudden, drastic change more than the average person, yet I still am not emotionally scarred from either divorce. Kids are tougher than you think.
There are two people involved in LizaM's marriage: herself, and her husband. If he continues to be unwilling to improve, it won't matter how hard she tries to maintain the relationship; it's gonna fall apart, and while it does, the tension is going to get higher and higher. It wouldn't shock me if her son is already suffering a bit from it.