As in life, it really helps to have a stay-at-home mother/nanny in the house.
Develop a routine. Mom gives Daddy a kiss before he gets off to work, then spends some time teaching the toddler. Take a quick break to snuggle-feed-crib the baby and tickle-feed the toddler, then use the bathroom. Wash those hands, brush those teeth, shower, change the diapers. Double-check that Daddy's dinner is hot and waiting for him, then get back to teaching Junior till Daddy comes home.
Usually this is as much work as Daddy puts in for a day's pay. This is fairly accurate to reality, which is why we should always respect the professional wife and mother as being the hard-working heroine, living up to her full potential in every way, as she is.
When Daddy gets home, the fire should be lit, the food should be on the table, and the younguns should have every need met so they can be ignored for a good 3 hours. Not a bad time for a nap.
EA decided that there's no such thing as a "quicky" when it comes to woohoo, which is why you need 3 hours after Daddy gets home. Want to up that fun meter and kill stress instantly? Woohoo!! So make sure Momma's wearing something sexy for dinner - you know, for realism.
Now you have the rest of the evening to not follow a routine. Maybe Daddy helps take care of the kids, maybe you all go to the park together, maybe you invite friends over. Whatever. 2 of you are home, he's not stressed out any more from "working hard", so things get a little easier. Just make sure that all the needs are met for the youngest ones before bedtime, and plan for Mom to get up 3-4 hours into the night. Do NOT wait for the crying or others might wake up, and you sure don't want Daddy going to work tired.