There is nothing pathological necessarily involved. You do not need to have anything "wrong" with you to hit gridlock--and there is nothing going "wrong" when gridlock hits.
It is part of a sequence created by the lack of differentiation that usually exists when we pick a partner: dependence on other-validated intimacy, a reflected sense of self, and regulating anxiety through relationships.
So what starts the differentiation process?
Typically it is marital problems caused by emotional fusion: sexual boredom, low sexual desire, lack of intimacy, fights about money, parenting, in-laws--and where to spend the next vacation.
The particulars of what triggers your differentiation are personal and custom-tailored to your past, present, and anticipated future. The people growing ecosystem in an emotionally committed relationship is amazingly circular; emotional fusion creates the "problems" that push us to become sufficiently differentiated to solve those dilemmas.
Here is something important to remember when your relationship seemingly grinds to a halt: when you and your partner reach gridlock neither of you can reduce anxiety through accommodation, and neither of you has any of the old kind of validation to offer the other.
Truly validating your partner when you have reached gridlock means accepting that he or she is less likely to accommodate you--you will have to confront yourself.
At the point of gridlock your choices are limited:
1. Push your partner to violate himself/herself by accommodating you:
2. Turn yourself over to your partner by accommodating him/her,
3. Separate emotionally or physically,
4. Confront yourself and become more differentiated.
Gridlocked couples report "falling out of love."
Ironically, the ability to love truly does not develop until the honeymoon is over and gridlock arrives. Gridlock drives you closer to your core as it nudges you towards differentiation.
As you get more firsthand experience with your own essence, you become more accepting of everyone else, including your partner.
Passionate Marriage - Schnarch