UK, Ireland / A Brit moving to Warsaw with his Polish wife [12]

I'm not an expert on family, but I would say it might be easier on you both if you live with your wife's family for a set amount of time, like 1-2 months, and agree right off the bat that you will rent a place for yourselves that is close to your wife's family, that way you and your children will be close to family but you won't be in the same space (I'm guessing smaller space than you are used to) for months.