Not sure what the therapist meant by it is only needed every two weeks. Maybe she/he meant that, at a minimum, or that the "average" couple did it every two weeks. But don't let that make you think the problem is yours. I firmly believe that there is no magic number, but rather, the issue is one of mismatch. If you have two LD people and they are both happy with once a month, then that is an appropriate number. If you have two HD people and they are both happy with once a day, that is an appropriate number. The problem comes in when those two couples switch spouses, so to speak.
PF
Me; 42, W; 43 M; 16 yrs S12, D9
3/13 - "I want to move to XYZ City (four hours away) and it might be without you, not sure" 5/13 - "Not sure I meant that"
