Describe the three steps that cause water to change during the water cycle?
Condensation --> Precipitation --> Evaporation
Is it true that once a partner is unfaithful this may cause a disturbance in the female's menstruation cycle?
The menstrual cycle is the entire reproductive cycle, I think you mean during menstruation. Diarrhea can occur due to the chemical-like hormones that cause the uterus to contract to push out menstrual flow, these can also influence the bowel. If you have problems then regulate hormones and improve diet.
There are naturally occurring variations that affect climate and the cycles are different: The Eccentricity Cycle (Elliptical Cycle) - This occurs about every 100,000 years and is the longer cycle. It causes the earth to cool. The Obliquity Cycle (Axial Tilt) - 41,000 years. Increased obliquity can cause summers to be warmer and winters to be colder. The Precession Cycle (Wobble) - This cycle occurs every 26,000 years and can cause seasonal changes.