Because of a family feud, he never spoke to his wife's parents.

Problem : a matter or situation regarded as unwelcome or harmful and needing to be dealt with and overcome.
Quarrel : a heated argument or disagreement, typically about a trivial issue and between people who are usually on good term.
Crisis : a time of intense difficulty or danger.
Trouble : difficulty or problems.
Feud : a prolonged and bitter quarrel or dispute.

Synonym of Feud is Quarrel