How can I spice up my husband and my sex life so he'll want to have sex again?

Talk to a sex therap. Or find out what what he like.
As below. Become friends and your sexual interaction will be positive.
Sex. Depends on the cause of his not wanting to have sex. This can be psychological or physical or a combination of this. Your husband should have a physical exam to help determine the cause. E.G. Some men have a physical cause related to the amount of testosterone they are producing, causing a relative deficieny in testosterone which can cause the problem.