I've been told that sometimes a low desire on the part of the wife is linked to how she is treated outside the bedroom. I dont know if it pertains to your case...but I can assure you.... once I paid attention to this, I had no other problems with my (now) EXW ....nor my current GF in that dept.
To me...it's simply a symptom of another unrelated issue in the R. But what do I know ?
