It boils down to you have to make a choice. You either get married and don't accept the class date or you **** off your soon to be wife and pospone the wedding to accept the class date.
I know from experience with this. I was offered a position in the left seat of a SAAB several years ago and I knew that the class date would probably overlap my wedding and honeymoon when I interviewed. I told the folks in the interview that I could not accept a class date during the time span of my wedding and honeymoon.(because I all but knew for sure that I was hired....not trying to sound cocky but sometimes you can just tell) They said that it was NO problem, and they would work with my planned schedule and that they would be in touch.
I know you might think the story stops here, but no. They called me a couple of days later and offered me the Captain possition with a class date DURING THE TIME SPAN I TOLD THEM I COULD NOT ACCEPT. I explained my situation again to the gentleman who called me with the offer, and he said no problem and they would call me later with another class date. They did, but it was the same class date and I explained my situation again. Again, they said no problem. I waited a couple weeks to hear back from them and started to get concerned. I called them several times and finally got in touch with someone. They basically said thanks but no thanks.
My point is you HAVE TO work with their (the hiring airline) schedule or forget about the position. Again, it boils down to making a choice.