Never betray your spouse emotionally. Risk being ridiculed and rejected by your spouse. Risk letting your partner see who you really are. Take responsibility for your own mental well being. Don't blame the other party if you feel worthless.
Silence can be worse than anger.
Of course, there are also times to contain oneself as well. Be ready to listen. Learn how to argue. Allow your spouse to be a different person from you, with different attitudes and some different values. Be ready to sacrifice some of your own personal pleasures and desires for the good of the marriage.