My initial guess is that it has roughly a neutral effect in the aggregate, but that on an individual level, if it has any consistent effect, it probably slightl

My initial guess is that it has roughly a neutral effect in the aggregate, but that on an individual level, if it has any consistent effect, it probably slightly amplifies whatever dynamics are already present in the marriage, i.e. it helps happy marriages and is unhelpful for troubled marriages. Reasons why it might help happy marriages: It allows you to spend more time together, even if you're not technically working together. You can have meals with your spouse. And it fosters feelings of security, e.g. "If either one of us were to have a serious emergency, the other would be present." Reasons why it might be unhelpful for troubled marriages: If the spouses are working separately but in close proximity, there's just enough togetherness for each spouse to irritate the other, but not enough togetherness that they can actually work on their problems.