I have a very, very small circle of friends.  My best friend wants to have a destination wedding in Mexico, and asked if I would be the best man.  It is about a year away.

Thing is, my wife and I don't have passports, and at the time of the wedding our son is barely going to be a year old.  When I told him I am honored to be his best man, but with our new baby and the finances of the whole trip I am not sure if I can swing it.

He offered to co-op the cost of the tickets for my wife and I but I would feel guilty as hell for accepting money, and on top of that I would still have to pay for a hotel, rental car, a baby sitter, etc.

Am I(or would I be) the asshole/bad friend for declining?