I am writing a story with a three crisis structure. The first is an external crisis that has the hero rushing to the rescue of the heroine. Then their relationship develops at a brisk pace, in the manner of "too much, too soon." The novelty wears off, and one or both recoils at seeing the other "real person," creating the second crisis.
After they are reconciled, they make it towards the top together, and this causes the third, decisive crisis. One wants to continue reaching for the brass ring, and the other wants to "kick back, relax, and take some time off with someone I love," basically two conflicting goals.
Do I need an external crisis for either the second or third crises? Or is it plausible that the characters run the risk of being victims of their own success?