Second Thoughts often run randomly throughout BDSM relationships. Many dominants just walk away in frustration when disobedience is constant and questioning is never ending. They begin to second guess their abilities to choose a compatible play/love mate.
Just as many submissives have second thoughts every day wondering if there really is any reality strong enough to fulfill their needs and desires. They often lose hope when dishonesty meets vulnerability.
Second thoughts left to fester are always destructive but those same thoughts faced head on and discussed in honesty are breeding grounds for hope and progress.
Small doubts can open new doors and be the beginning of new techniques or the desire to try new mind fucks. Larger doubts or the consistent erosions of the natural flow between the dominant and submissive even if they do not cause the dominant to question their style of domination may cause then to question their choice of a partner.
It often troubles me to see others walk away from this lifestyle (even temporarily) because of the doubts caused by the interaction or lack of it between them and their BDSM or D/s partner that is less than they perceived it would or should be.
Doubt within a relationship should be greeted not as unsolvable problems, but as opportunities for growth. I would suggest that working on the doubts as they come up rather than sweeping them under the carpet and hoping they will take care of themselves can turn a negative into a positive.
Running from them actually increases self doubt and adds to the doubts of the partner as well. Even doubting the validity of a relationship and making excuses for hanging on weakens each of the partners but letting go in honesty can add strength to what was once between them.
The complexities of life are stunning in their fragile beauty!