This was a good point:
If The mounting pressures of day to day life are not enough they also have all the pressures of being a jw.
To the extent that the couple devotes themselves to the endless demands of the Watchtower Society on their lives, it tends to take time and energy away from each other. They still are sex partners (hopefully) and life partners, but the time spent 'putting on appearances' and keeping one's reputation going in the congregation takes its toll.
Also, you know that JW's always put the organization ahead of friendships. You are even expected to "rat on" your spouse if you discern any disloyalty to the organization in them.
I heard it said from the assembly platform that the popular saying "blood is thicker than water" does not apply in the families of Jehovah's Witnesses. In other words, family comes second to your relationship with Jehovah, erm, the organization.
So to the extent that they are "devout" JW's, to that extent their friendships with other JW's are conditional, and even their relationship with their own spouse is conditional.
I know, I've seen it!