After we had difficulty having children we then had a baby who was quite ill for a while and some difficult stuff to process around our parents as well. And some financial problems. We did well with our own relationship but felt it hard to really enjoy having sex with each other and there were practical reasons why we did not feel able to "let go" without someone being there to be on call for the baby and that had to be one of us really.
We didn't want to have affairs and we had so much counselling and therapy both together and separately we found it possible to raise ideas that we wouldn't have raised before. This was one of them. It wasn't easy but by the time we actually did it the level of communication had improved so much between us,we felt weird, but OK.
And now it's made sex less taboo. less of a big deal. Less of a sense of failure that we can't achieve everything in life and an amazing exclusive sex life too as a partnership.
I think the only other path would have been divorce as the lack of honesty about our needs, not the lack of sex, would have driven a wedge.
I have been vulnerable saying this. I ask people to respond kindly rather than triumphantly picking holes like "aha, you had problems already, that's why you couldn't hack monogamy!!" I mean yeah, that's true! It's vastly easier to tread the beaten path.
For DH and I, the rest of life was particularly hard and it affected our bond. So we reset our bond and brought joy back to our lives and marriage by doing this. We could have made our sex life the thing we compromised on. We'd still be together, probably, but with some resentment.
I have no doubt that we will retire together and die together. That's where it becomes hard to explain why these things are good - if I say it's great now, people say I'm shallow. If I say it's great because we have a deep underlying bond and he is my soul mate, I'm sort of taking the values of monogamy to justify why it works. So I don't think I can. I only know we are happy and I assess there is more honesty and authenticity between us. DH would say the same, but obviously you only have my word for it!