How can a young man rid himself of his obsessions, excessive fear, and intense jealousy regarding his fiancée, which cause him psychological distress even when she goes out with her parents?

Jealousy is of two types: praiseworthy, which is when a man sees his family engaged in a forbidden act or in a situation of suspicion; and blameworthy, which is jealousy in situations that are not suspicious. So, if your wife goes out with her parents in a manner that is not suspicious, there is no need for psychological pressure, obsessive thoughts, and doubts. These are from the stratagems of Satan, and one must strive against oneself to get rid of them and turn away from them, and frequently seek refuge in Allah from Satan.