Oklahoma: I suspect you will already have tried many of the suggestions you will receive. Your husband will probably need more help than he can get on an internet forum. Becoming secure and able to meet your own emotional needs requires a lot of work to overcome, and it's roots probably lie in childhood experiences.
The treatment of choice is Cognitive Behavioral Therapy. Here is a link that provides more information.
NAMI | Cognitive-Behavioral TherapyOne question you're going to have to ask is "Is the relationship problem a result of the insecurity or is the insecurity a result of the relationship problem?" If the insecurity wasn't going on before the relationship problem then the two of you will need a compassionate marriage counselor. (And, yes there is a relationship problem.)