Spinach & Artichoke Dip help?

What sort of recipe are you using? If it contains sour cream, add it at the end. When you heat it and it cools, it tends to separate. You can put it in a pan after the ingredients are mixed and heat it on medium-low, stirring frequently. Since the cream cheese will already be soft, it should heat rather quickly. Just keep an eye on it. Microwaving will also work, but it doesn't heat as evenly-though I do reheat mine in the microwave.