Doubt, paranoia

First, judging from your personality, you are a thoughtful girl. You are considerate and cautious. People with big nerves generally don't doubt anything casually, so your personality factors have an influence on your thinking habits and acting style.

Second, your whole article only reflects one problem, distrust and doubt, especially for your fiance. Because of real life factors (the wedding day is coming) and personal cognitive factors (men can't be trusted, only family members won't betray; The problem becomes obvious.

Thirdly, if your problem is just distrust, then it is not possible to solve the problem from the source by deeply understanding the root of your psychological problem. If the above situation affects work or life and cannot be alleviated through self-regulation, it is recommended to consult a psychologist face to face.