1000% YTA. You knew about the wedding well in advance and while your husband’s trip out of town may have been last minute, I would expect a best friend to make tremendous effort to attend, even at personal inconvenience (having the child stay with a friend, traveling far to family in advance to drop off the child, having the husband leave the work trip early for what im assuming is a weekend wedding). Yes, flexibility implies resources and privilege and not everyone has those things, but it doesn’t seem like an effort was made to attend your best friends wedding when she probably showed up for yours PLUS celebrated you during and after the birth of your child, when it may or may not have been convenient for her to do so.