Answer:
Cheating and misunderstanding
Step-by-step explanation:
The baseline of the love is based on the compatibility and understanding means how much the two partners understand each other and how they support each other. If the understanding is not up to the mark then it will be the major cause of breakup.
The second thing in the love is loyalty, it is most important factor in any relation, if any partner is not loyal towards other then there will be more chances to end up the relationship.