While there is no sex involved, such a relationship can create close attachments and as result impact a marriage. When you have children, it seems to stifle the intimate stuff for a while, but normally, it comes right back in time.
Well, the healthy thing you can do about it, is to consider getting some supportive professional help. That's how a relationship is supposed to be. Emotional detachment does not just happen out of the blue; there is always something behind it.
We end up fighting about it and I get all worked up and admittedly say stupid things. You don't have to journey alone. If she is going through an anxious period in her life or a lot of stress is bearing down on her, these things can get in the way of the brain chemistry that leads to sexual interest.
A healthy relationship is all about equality, with each partner doing their part to make the other person happy.