text: There are no technical terms for a person who is suspicious about his/her significant other. There may be psychological theories about such behavior, but psychology/psychiatry as cannons of study do not institutionally recognize a single term. Don't believe me, search the DSM-IV-TR or the ICD-9, but you won't find anything. If the significant other's suspicion is problematic to the marriage and seems to interfere with daily functioning, then perhaps this suspicion is a symptom of a larger problem, but much more detail would be needed for a diagnosis.