If the marriages in The Great Gatsby are anything to go by, we want nothing to do with marriage. Love? Optional. Loyalty? Definitely not. The only marriages we see are marked by adultery, deception, and dissatisfaction. Gatsby thinks that his life (and Daisy's) would have been better if she'd chosen him instead of Tom, but we're not so sure. Fitzgerald seems to take a dim view of marriage in general. Based on his relationship with Zelda, we can understand that.
The Great Gatsby suggests that love and trust are mutually exclusive.
Although Fitzgerald suggests that infidelity is widespread in society, he also seems to approve of staying together. The Great Gatsby believes in marriage, even if it sees the negatives.