Sims merried on sims life stories

If you want your Sim to be married, you have to increase the relationship with another Sim. Once they are in love (check the relationship panel), you have the option to choose 'Propose..' in the socialization options. Choose this, and then 'Propose Engagement' - if the other Sim accepts, your Sims can then get married. Either buy an altar (in Buy Mode, it is in the party section) and select the 'Get Married' interaction, or choose 'Propose Marriage' in the socialization interactions. Then, your Sims will be married!