Sex only when he wants to....

I've been with my husband for 9 years and whenever we have intimacy it is AMAZING, but we don't have sex as much as I would think the "normal" would be. For example: las month we only did it 3 times... 3 TIMES!!! And whenever I want to be intimate with him there is always an excuse, but whenever he wants it I'm good and ready, cause sh$& if the opportunity comes, I'm going to take it. Am I thinking too much in to this?