it seems that you have a common type of OCD.
i know you are worried about your husband, but YOU know he will not cheat on you and YOU know that he is ok, so when you begin to have a thought like that, try saying, "Its not me, its the OCD" and try your absolute HARDEST not to call or think about him dying. I know its hard, it will NOT be easy, i am going through the SAME thing with my fiance. but all i do is i tell him, i told him about how i have OCD and how other people do to, how all i need is to be helped and tell him that im constantly worried about him dying or getting hurt and that its normal for people to think like this and you can over come it, but i just need some help. he took the time and tried to understand everything that i was going through and still to this day he helps me. i really think you need to just tell yourself "Its not me, its the OCD" confide in your husband and don't let this control you. Prozac works the best, dont be embarrassed. Go to your doctor, say i think i have OCD, im constantly worrying, i want something to help me and he/she will give you some kind of prozac or pill to help. and they DO help more than i can tell you. you feel a LOT of relief but you CANNOT just hope the pills help, you need to learn to help yourself! Trust me. you can do this
Good luck
Kellie