Questions like this are regularly asked online by different people who have one way or the other realized the dangers such an attitude poses to their marriage.
Of course, without even overemphasizing on this fact, you should know that pure and unadulterated trust is the bedrock and root of the sustenance of any marital union.
Without trust between spouses in a marital setting, such a union is literally sitting on a time bomb which is ticking down and if not properly resolved will definitely disintegrate.
The only way to save your marriage from thinking that things that are non-existent are happening is simply by building trust.
By building trust, I do not mean that you should build blind trust just for the sake of building trust.
You can only go ahead to start cultivating that trust without much ado if and only if your spouse has never exhibited a questionable character.
In order to solve the problem at hand, you will still have to build that trust even in the case where your spouse has shown or exhibited a questionable character previously but before you start building that trust in this case you have to sort a few things out.
It will be foolhardy for me if I advice you to go ahead and start building a certain trust around your spouse even when it is known that your spouse has previously done some of the things that you are now falsely thinking that is happening.
In this scenario, the best thing to do is to seek professional counseling, while your spouse would have to totally drop his former habits, you will on own then start to cultivate some trust in your husband.
This may involve a lot of work but at the end of the day, it is hard work that is worth doing.
While seeking professional help, you should take advantage of any of the many good save your marriage guides that are available online.