Good points from millicent, but try not to read into his motivations. Maybe he does want you to go, he didn't have to ask you, you know!
Could you tell him that you don't want to infringe on his time with his d, but you'd like to plan a date for next week? Also, it might be a good idea to let him know that it's important to you that you hear from him at least once while he's gone. Remember that part of DBing is asking for what you want.
