Wow, that’s a very selctive definition, especially if taken literally - you put “and” rather than “or”, and especially if you mean “chronic” in the proper sense of “long-term” rather than the popular sense of “really bad”.
I was in a very unhealthy marriage indeed. There was no domestic violence. There was no substance abuse. As far as I am aware, there was no infidelity. If there was (and I had my suspicions at the time) then it was only in the last few months when the marriage was already dead in the water.
Fortunately, there were no kids.
My unhealthy marriage was unhealthy in that we were unable to stay in the house together for even one evening a week. We couldn’t discuss anything amicably. We ended up hating the sight of each other, having found that once the initial excitement of lurve had worn off, we didn’t actually like each other. It drove me to the edge of suicide, and after I left, I’m given to understand that the “backlash” put my wife into therapy. That unhealthy enough?
So, less of the tightly worded definitions, please.
I was the child of divorced parents. They divorced before I was old enough to understand - and that was around 1964. I was told I was the only kid with divorced parents in the whole school, and it was a matter of shame and secrecy. My parents never spoke civilly to each other until my grandfather’s funeral in about 2003. I never saw domestic violence or solvent abuse, and I believe there was no infidelity. I’m sure the experience of mutually hostile parents shaped my life and personality.
But on the other hand, my partner/girlfriend, Ruth has two kids (now 21 and 23 (er… I think) and divorced from their father when the kids were around 8 and 10. They were at school surrounded by other kids with separated or divorced parents, and although it wasn’t always easy, it was fairly normal for them. Both parents loved the girls, and they had a fairly stable life, spending time with each parent, and both extended families on a predictable and regular basis. They’ve grown up to make their parents and me very proud.
The effect of staying together or separating, staying married or divorcing will vary depending on the social context. However, the effect of constantly being exposed to an atmosphere of hostility in the house will always be bad - whether it is cold hostily, or daily shouting matches, or mild or serious violence. Kids need stability, and good role models, and a caring environment. Whether the parents share a bedroom, or even an address, is less important.