Spouses living separate but not divorced

A marital life is that the husband and wife live in harmony together. This is going against the grain of marital life. In a few days they may have children or they already have children and the children need parental direction. The wife needs support and the right direction from the husband. How is this going to be possible if they live separated. And then the worst scenario is that when they are going to be living separately then the possibility of them becoming victims of shaytaani thoughts may be greater.

And Allah Ta'ala (الله تعالى) knows best.