We are friendly/cordial with DD's in-laws but only see them a couple of times a year when we visit DD. DH and I were completely surprised to hear that they are celebrating their 50th anniversary this coming weekend with a party and dinner. However, we did not receive an invitation to the festivities and don't know what to make of it. It kind of hurts to be excluded. Whad'ya think? Are we being too sensitive about this?