What is the way to deal with a fiancé's extreme jealousy that has reached the point of suspicion, and will this suspicion continue after marriage?

A man's jealousy over his honor is praiseworthy in Islamic law, but excess in it is blameworthy. The suitor should be moderate in his jealousy, and the fiancée must adhere to the legal hijab (definition) and avoid mixing with non-mahram (definition) men except with strict controls, so that he does not wrongly suspect her without proof. If the suitor changes his ways and it is hoped that matters will stabilize after marriage, then the marriage should proceed. Otherwise, we advise dissolving the engagement if there is a fear of instability due to his jealousy and suspicions. Engagement does not permit forbidden acts such as seclusion (khalwa (definition)), looking (nazar), or touching.