Hope, reading your signature, I wonder if the person who is taking the initiative to repair the R can't 'afford' to feel that it's too hard, while their partner, who is asked to participate, can allow themselves to feel that.
I do feel sometimes that it's overwhelming, that H and I are just too different as individuals to make it work (it seems we have become more different as time goes by, or maybe H has stopped hiding who he really was all along), but I don't feel that the work is too hard for me - it's more that I wonder if we have the basic connection that even makes us want to be together. If I had met H today, I would probably never have wanted to pursue a relationship - our values, views and temperaments are so opposite that even the counselor wondered how on earth we ended up together.
Good job on recognizing the tone in yourself!
M 16 yrs, WH62, P54 3 adult blended kids EA 11/13, BD1 6/14 PA fall 14, BD2 2/15 Piecing 2015, BD3 12/15 Separated 4/16 WH moved OW in 5/16 Divorced 6/15/17