If you and your spouse's ex have different discipline styles, here's what you can do to bridge the rules gap:
Let Your Partner Do the Talking
He and his ex should discuss your household rules without you. "A stepparent is generally not going to be well received by an ex-spouse," says Mark Fine, a professor of human development and family studies at the University of Missouri.
The goal: to establish rules that aren't too divergent, such as bedtimes within half an hour of each other. If the other parent is resistant to compromise, ask your spouse to remind her that it's in the children's best interest. "Kids like consistency, security, and stability. It's difficult for them to switch gears between houses," says Fine.
Trust the Kids
For those issues you can't agree on, discuss them directly with your stepchildren. "Say, 'This house isn't the same as your mom's -- we have our own rules,' " suggests Susan Ginsberg, author of Family Wisdom. Kids can be flexible if they have to -- just as they're able to understand that the rules at daycare or preschool are different from those at home.
Try Transition Tricks
You and your partner can help your stepkids adjust each time they come to your house by reminding them of some general rules, such as when they have to get ready for dinner.
Another way to ease them back into your house is to give them a grace period of an hour or two. "Kids need to have some unstructured time when no demands are placed on them," says Fine. As long as they know they have your love and support, adjusting to different sets of rules shouldn't be a problem.