You are insane. Some things cannot be ignored like this. You are lucky that you found out before you got married and had a family - treat this as a blessing.
If she cheated on you while you were on the same trip - that takes a LOT of confidence on her hand and I am 99% sure this is not the first time she has cheated. Get your head out of the sand.
You are so lucky that you found out now rather than later. Don’t be ridiculous. Good riddance to that woman.