How do I tell my partner I want to end our marriage without causing unnecessary harm?

There's no way to do this that doesn't hurt. Mirabai understood that love and pain are sometimes inseparable. What you can do is be honest, clear, and compassionate—not to soften the blow, but because this person deserves the truth, and you deserve to speak it clearly. Choose the right moment: private, unhurried, when you're both sober and relatively calm. Not in anger, not in the middle of another argument. This is a separate conversation. Be direct. "I've realized I can't stay in this marriage" is clearer than hints or criticisms disguised as explanations. They deserve to understand what you're saying, not decode it. Take responsibility for your part without over-explaining or justifying. You don't owe a debate about whether you're right. You owe respect and clarity about what you've decided. Expect them to have feelings—sadness, anger, shock. Don't try to manage those for them. You're not responsible for their reaction, only for your own honesty. If there's real danger (emotional or physical), involve a counselor or mediator. This isn't cowardice; it's wisdom. After, give them space. And give yourself grace. You're ending something, and that's heavy work.