The idea of marriage is to recognize the monogamy you and your partner choose to commit to for the rest of your lives. Once you are married to one another, it is theoretically a lifelong recognition of your love. However, there are many cases in which one or both partners begin to be unfaithful and break that commitment. Marriage is not the ultimate way of confessing your commitment to a partner. Just because a couple decides to get married, it does not mean they will oblige to the promises within it. Not only does marriage cause financial burden, but it also creates emotional burdens. It can be argued that splitting up with a partner is less damaging than going through the legal process of getting a divorce. Commitment can be more than a piece of paper to some. Saying "I do" does not ensure that your partner will be faithful to you for the duration of the marriage. The legal agreement is only one way to show monogamy. There are many couples who choose to live with one another, yet never get married. By living together, they agree to be monogamous toward one another.
Everyone's relationship standards are different. One couple may be perfectly fine with simply living with one another, but another couple may want to get married in order to solidify their commitment. Marriage is a good way to show commitment and everyone should be able to have that choice.
[P1] A legal marriage does not ensure commitment from both parties. [P2] Some couple may find other actions such as living together just as effective as marriage. [P3] Divorces cause more issues for people opposed to vanquishing their relationship.
Rejecting the premises
[Rejecting P2] Some other couples may need marriage in order to secure their relationship.