After you have completed all the necessary steps (as outlined in the Marriage section), give the girl you like the Blue Feather. If she accepts, the two of you will be married 7 days later.
The wedding will take up the whole day, so there won't be any time for farming. The next morning you will be with your new wife in your farmhouse. She will ask you what name you would like her to call you. You can choose from one of the default names or you can pick a new one. If you're married to Elli or Mary, she'll tell you that she's going to continue to work. If you're married to one of the others you can choose if she should stay home or go to work.
Your wife doesn't cook you breakfast in the mornings or dinner at night, but she will cook on special occasions like your birthday and wedding anniversary. Most of the time she'll just walk around the table all day long. She won't help you with any farm work either. Some of the festivals change because of your marriage:
Summer 24 / Fireworks -
Your wife will watch the fireworks with you. You don't even need to talk to everyone on
the beach like you would if you were going to watch the fireworks by yourself. Just talk to
your wife to start the festivities.
Fall 13 / Mother's Hill - When you weren't married, the girl with the highest affection would meet you at the top of Mother's Hill to watch the full moon. That's still the case even when you're married, so don't expect it to be your wife all of the time.
Winter 14 / Thanksgiving - Instead of receiving gifts from the other girls, you'll receive nothing at all. That's not so bad, since when you go to bed that night your wife will get up and make you some Chocolate Cake. Instead of leaving it on the table she will leave it in your Rucksack for you to find later.
Winter 24 / Starry Night - Instead of going out with your wife's family, the two of you have a nice party at home.
Wedding Anniversary - When you reach the day the two of you were married, your wife will be waiting for you in the morning. She asks if you know what today is, so make sure you remember when your anniversary is! If you answer correctly, your wife will give you a gift.
About a season after you two are married your wife won't feel well one morning. When you take her to the Clinic, Doctor says she's not sick but she's actually pregnant! Your wife will be quite happy about the new baby. Now you just have to wait 60 days until your wife gives birth. She'll go around her business like normal until the 60 days have gone by. On the morning of the birth, Doctor will come by and help with the delivery of your son.
Now you may have a son although he isn't going to be much fun as a baby. Your wife will carry him around when she's home, but if she has to go to work then the baby ends up in the bed until she gets home. You can't talk to your son at this stage and you can't even give him gifts.
After another 60 days your wife will wake you up in the morning. She says that when she woke up she found the child on the floor! Your baby is crying and looks like he might be hurt. Your wife will ask you what you two should do. You can reply that he'll be fine or if you think you should take him to the Clinic. If you tell your wife that he'll be fine, she gets mad at you and takes him to the Clinic anyway. The correct answer would be to volunteer to take him to the Clinic in the first place! When you all return home your kid now can crawl around.
Once your little squirt starts crawling you can finally start to give him gifts to raise his heart levels. Your kid likes Cakes (Cheese, Hot, etc.), Ice Cream, Honey, Yarn, Grapes, Milk recipes, and Noodles.