I don't know if this will help, but OK this with the girl your engaged to first and tell her of your concerns.
Boys should be taught at a young age that girls are fragile and can not be rough-up even in a playful way. This will serve the boys well when they are older.
You might even mention to the boy that when he gets older, often there's a chance some of the women around him might be pregnant and not yet showing it, so it's wise to get into the habit now of never treating a girl rough. I once saw a man pull a bar-stool out from behind a woman as she was sitting down, so she fell to the ground. Later I told him that I thought that was one if the dumbest things I had ever seen. What if she was pregnant and not showing yet, and lost her child. I think he realized how dumb he had been.
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There are 2 kinds of punishment that should never get the adult in trouble that I know of.
Ask the offending child how old are you?
After they answer, say one of 3 things:
That was a minor offense you just did. Go sit ( and name a place ) for one minute for each year of your age.
That was a serious offense you just did. Go sit ( and name a place ) for 2 minutes for each year of your age.
That was a very serious offense you just did. Go sit ( and name a place ) for 3 minutes for each year of your age.
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Another thing to keep them in line. If you don't ( behave, stop that right now, or however else you have to tell them to behave properly ), I'm going to go to where you keep your toys, electronic stuff, exc, and I'm going to chose something and give it to charity. And you will never see it again. ( Note, now days cell phones and laptops may have a tracking app installed, so if you go that serious, you have to somehow prevent that from working, such as physically destroy it.)
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I know that both these types of discipline work. OK that you can apply them in advance.
Actually giving their toys to charity usually only has to be done once or twice and they catch on that when you say you will do that you mean it, and they don't know what they will loose so they don't take the chance.