Cody's more than happy to have sex, he may even be willing to offer his submission, but experience has taught him that's as far as he can go as a gay man. Tristan disagrees…
Tristan has being gay all worked out rather nicely. His biggest problem with his sexuality is his mother's persistent attempts to find a nice young man to marry him off to. And even that doesn't seem like such a terrible thing when he arrives to have dinner with his parents and finds Cody sitting at the table.
Homosexuality isn't working out quite so well for Cody. As far as he can see, Tristan's appearance in his life is unlikely to make things any better. Nice guys rarely stay nice for long and dominants have a way of turning into complete psychos if he lets his guard down.
Cody needs to walk away before Tristan tempts him into wanting the sort of happiness he knows he can't have. Tristan needs to stop him.