Putting them on pause, meaning you know she’ll continue relationships/dating others when you’re married already? I believe staying with her just for the sake of the kids is wrong. You’re crippling your chance of having a wonderful relationship with someone else, because you want to give the kids the illusion of a functional family.
If your fiance can’t change, after you confront her about the other guys, IMO you should leave her, but continue to be a father to your children. It does not always have to be both stay with spouse and kids, you can have your happiness while also giving your children a great life. I know a lot of people who stay in their marriages just for the kids, they end up taking out their frustrations on everyone, even the kids themselves.
Thank you for sharing Q