Premature ejaculation is a functional disorder. During premature ejaculation, no organic disorder of the genitals is present. Premature ejaculation is usually due to lack of sexual experience or anxiety. Since you are 39 and married with 2 children, we can most likely exclude inexperience as a possible cause, leaving anxiety as the remainin diagnosis. You may need medical help from a mental health doctor like a sexologist. There are some medicines used for treating premature ejaculation such as selective serotonin reuptake inhibitors (SSRI) which can be prescribed. But more likely, a combination of psychotherapy and pharmaceuticals can help you.