Mental pressure. Do to not doubt on him.

Hi. Am a house wife it's been 3 years for my marriage. My husband loves me a lot and takes care of me very well. I don't know if I do take care of him that much. My problem is I always doubt on him. Keep thinking of him always like what he is doing with whom is he chatting and all. Am not relaxing my self am so possessive on him don't want anyone to be close with him. He is very genuine. He is not a character of a that kind(like cheater or anything). When ever I doubt on him I ask him directly but he politely listens to me and say I have to take the doubt of my mind there us nothing to doubt him. And now he tells if I keep him doubting all the time he might do anything wrong. I don't no what I have to do. Why am I doing like this. I want to relax my self. Don't want to think about him always and give a mental pressure to him. He is already busy with his business and I don't want to tourcher him a lot. Please give me solution what should I do and what should I do to not doubt on him.