Insecurities

How do you get over your insecurities . Mine is I am afraid my husband cheating on me . I hate to see him and his co workers talking . He tells me my insecurities will destroy are marriage if I don't learn to get over them . He says he loves me so much and it hurts him to see me being so insecure . I am just so paranoid over it . Idk how to get over it .