I get this. You say he broke his plans with you to go on an outing with him instead. No, you are not concerned unnecessarily. Your feelings are valid. I certainly would be ticked too. How often is this happening? Is this friend single? What kind of man is this friend? Does your husband ensure he is spending most of his time with you? Are you going out without him? If this is an occasional thing with a settled down buddy I see no problem. It would be no different than you grabbing coffee with a friend of your own. If this is constant though and at the cost of your own time with him then it very much to me is a problem.