Do you think he's cheating?

My husband came home from break yesterday and he sat down to eat.. Then out of no where he asks me '' do I have a red mark on my neck? '' and I'm like umm yeah.. (I didn't even notice it when he came in) and then he's like '' a piece of wood fell on my neck '' and I just said '' oh OK '' and we just went on with our eating.. The Thing Is that it's a red bruise and I'm starting to think it's a Hickey.. But would he just ask me about it if it was?? He never cheated on me and we have a one month old son.. Should I be concerned?? I'm getting paranoid.