Raising children in two households is one of the biggest challenges faced by parents after separation or divorce. Parents who are used to letting their spouse be the disciplinarian have to step up and be the "bad guy" occasionally when their kids are with them. Another challenge is that you and your co-parent likely don't have the same parenting styles.
However, while you won't have exactly the same rules for each of your households, it's important to provide your kids with some level of consistency and predictability so they know their parents have basically the same expectations of them (doing their homework, keeping their room tidy and not swearing, for example) regardless of which home they're in.
This may be a good time for you and your co-parent to establish some "official" household rules that apply to both of your homes. These should be rules that apply to all of the kids, regardless of their ages -- and to both of you, if you want to be good role models.
If your kids are old enough, ask for their input. They'll have a more positive attitude about the rules if they feel like they had some say. They'll probably also be reassured to see their parents working together despite their differences. You can also give them responsibility for enforcing the rules themselves when they have friends over. For example, no graffiti on the walls or taunting the cat needs to apply to everyone who comes in the house.
Once you've established the rules, make sure the kids understand them. Perhaps you can post them in both homes. This will provide a symbol of consistency as they move between houses.
Making the rules is just the first step. You have to be willing to enforce them. That means setting specific consequences for what will happen if the kids break the rules. Each parent has to be the enforcer in their own home -- unless the consequences extend across your custody schedule. If "no TV for a week" is the punishment, you may both have to be the enforcers.
If your co-parent has a problem enforcing rules like getting homework done or reasonable bedtimes, and your kids are negatively impacted as a result, you may want to consider making modifications to your parenting plan to include more specifics. Your Missouri family law attorney can help you if you seek to do this.