Sorry u r in this situation. It is really a no win. The kids r young & sound like they have been thru a lot in 2 years....divorce, remarriage, engagement, new authority figures. IMHO it's going to take time for them to learn ' different home, different rules'. Just like any kids, if they r having fun they don't want to stop. They haven't learned much self-control at their young age. It all just takes time & growing up. As long as there is no abuse, etc there's not really much u can do but be the best parent u can when they r with u. Perhaps a rountine to help them get ready to leave would be helpful for them to transition back to their Mom's. Something conveniently repeated at the end of every visit. For example: put toys away, pack bags & put in car, order pizza, leave. Not rushed. Just a rountine that signals to them that the visit is coming to an end.