Dealing with trust in a relationship. Long... Sorry :(

Ive been married almost 4 years and i still have Trust issues with my husband. He does not give me reasons to think he is cheating or anything its just me!! I dont know how to control it. We have a daughter together and another baby girl on its way. We deleted pur FB for the same reason and we currently made a new one together and deleted it the 2 day just because i asked him why he had added one of his friends which was a girl. He got so mad and said to delete it. Idk what tp think was it because of that specific girl that he got all mad or what! Makes me think!! I wasnt trying to confront him or anything and he just got all crazy. What should i do :( i really want to be happy. Maybe its just that my self esteem is low which makes me keep thinking all crazy!