DH backing out

DS has a stepson who is graduating from a Fine Art course at Oxford Brookes this year. They have an end of year art show in the Summer and a couple of weeks ago DS rang me to ask if DH and I would like to go down to Oxford with them for the weekend to attend the preview show and a reception. SGS has also been chosen to give the graduation speech. I asked DH and he said yes ok. Today, he said he didn't want to go, it isn't his thing and he would feel like a spare part, so he would stay at home and I could go because "you enjoy all that stuff and you can talk to people about it". I'm so disappointed with him. He rarely wants to do anything that involves mixing with people recently. I think it is because his hearing is not that good but he says that's got nothing to do with it. Now I have to either go without him, or not go. I feel rather let down by him.