1. Her children's games are the only ones she wants to play.
So don't waste her time with yours. Feel like she's perfect except you don't want kids? It's probably best you move along if either of you wants something long-term.
2. Liking kids isn't the same as raising kids.
Instead of pretending you know what it's like, ask questions and be humble. You might have a really fun time with your nephew at Christmas, but this isn't the same as cleaning up vomit at 3 a.m. Ask about what she loves about being a mom, ask about what her kids' interests are, admit that you've never seen Frozen.
3. Liking her kids isn't the same as raising her kids.
You might have some really great ideas about how you think she could do things, and you might have some strong ideas about how children should behave. Not. Your. Business. At least not until you're all functioning as a family unit, which takes time, honesty, and patience, and possibly some therapy.
4. Don't ask dumb questions on the first date.
"Did you ever consider an abortion?" is a dumb question. It's also a real question that single moms actually hear. Don't ask that.
5. Don't be surprised — or rude — when she hasn't heard the latest from Beyoncé or seen any Fast and Furious movies.
Planning time for mascara is hard enough; popular culture becomes the Great White Buffalo. Do make her a mixed CD and enjoy watching Netflix together after the kiddos hit the hay.
6. Throw everything you know about scheduling out the window.
Be ready for rapid-fire spontaneity or an ironclad calendar. You're at the mercy of custody agreements, parent-teacher conferences, skinned knees, stuffy noses, and — buy her wine for this one — lice.
7. Throw everything you know about Sunday Funday out the window.
Until the mini people are old enough to get their own cereal and turn on the cartoons, there's no such thing as sleeping in. If you really want to impress everyone, let her sleep while you get the pancakes going and put the coffee on, or take everyone on a doughnut run. Glazed old-fashioned might be the closest thing to a Bloody Mary you both can get.
8. Speaking of Bloody Marys, hangovers aren't an option anymore.
It's not about being in your 20s or your 30s or your 40s; it's about keeping it together during a living room performance of Annie and wiping butts and doing laundry. So much laundry.
9. Her ex might still be in the picture.
It's very likely he will be a large part of her life for at least the next 18 years, so get used to it. If she gets along with him, great, be cool. If she doesn't get along with him, also be cool. Be supportive if she complains about him, but whatever you do, don't talk badly about him in front of the kids (it's actually included in many custody agreements; don't make a sticky situation stickier).
10. She can't just see how the night goes and stay out as long as she might want.
Babysitters are people too, and good ones are a hot commodity. They deserve to be treated and paid well. If she told the babysitter she'd be home by 11, make sure she's home by 11! Say good-bye to after-parties, say hello to more-time-for sex (Lock the door!).
11. She's good in an emergency.
Goldfish crackers and Band-aids are never far away. What else do you need from her purse? Hand sanitizer, Chapstick, a small dinosaur, some crayons, or a flashlight? She's got it. Flushable wipes, duh.
12. She probably doesn't need saving, but she definitely needs a massage.
Handling what life serves is her modus operandi — she's been handling it since before you came along, and she's prepared to handle it if you leave. Don't pamper her because you pity her. Pamper her because you admire her Terminator strength to always keep going.
13. Pampering includes calling the babysitter.
If you want to whisk her away for a romantic weekend, offer to help with the parental logistics so she's relaxed on her trip, not distracted with worry. And don't make nonrefundable reservations. See no. 6 above.
14. Whatever you do, don't surprise them with a puppy.
There is nothing more beautiful than a joyful child. But unless it's a puppy that's going to sleep, howl, and poop and chew on everything at your own house, it's too much trouble for the 20 minutes that you'll be The Best Boyfriend Mom Has Ever Had.
15. Be willing to watch Frozen, whether you've seen it or not.
Also, be ready to play Frozen — it's very likely you'll have to be Anna over and over. And over, again.