It is hurting him to be with me and see that something is missing for me. Love ebbs and flows. As Steve says, it's not always fireworks. But you do need some passion to hold you together. I'm most worried about infidelity coming into play.
Many people use an affair to end a dissatisfying marriage.
Don't be one of them. End it first. As women, we often want and expect too much from a relationship. Perhaps you have more than you think and don't see it. Try other changes in your life to give you the pleasure and contentment you seek, like a new job or health regimen rather than a new partner.