To get married you must be at least level 6 with a relationship meter rating of at least 250 with your partner. You can check your relationship meter rating in your “Contacts” menu (smartphone icon in the lower right).
Date your partner as much as possible to unlock a quest called “Popping the Question?”; this quest will lead you to a fabulous wedding!
Balancing your celebrity life with your marriage will still require you to keep an eye on your relationship, so see your spouse as often as you can to keep the love alive!