The secret to a lasting partnership is that it evolves. How, why and into what depends on the people involved, but no relationship ever stays exactly the same. But sometimes, one party of the relationship evolves in a different way or at a different speed than the other. And sometimes, the evolution of a monogamous relationship takes a decidedly un-monogamous turn.

How we define love is individualized; love doesn’t necessarily mean one partner for sex, to every couple, says Mumbai-based clinical psychologist Pallavi Bhurkhay. But how do you navigate the shift? How do you even begin to suggest an open relationship to a monogamous partner? Bhurkhay, who frequently works with couples, advises below.

First, ask yourself: why do you want an open relationship?

Before even broaching with your partner a shift from monogamy to an open relationship, it’s best to introspect about your reasons. “What changed? What’s the purpose to go outside the relationship? What’s the need?” Bhurkhay says. “I see a lot of clients who are confused about what they really want from a relationship.”

Often, interest in an open relationship boils down to one of two driving factors, says Bhurkhay: something is missing from the monogamous relationship, or missing within one’s self. Maybe an open relationship is actually the solution; maybe it’s not — but you won’t know until you come to grips with your motivations, she says.

If it’s a matter of feeling your needs are not being met — have you discussed those feelings with your partner? If not, is it worth having that conversation first? “Many of us talk about thoughts; we’re not even aware of how we feel or why,” Bhurkhay explains. “Getting clear about your emotions and reasons for wanting an open relationship will help you be able to communicate them to your partner. And when it comes to suggesting an open relationship to your monogamous partner, and then enacting it, “communication is the key – you have to communicate to your partner what you’re feeling and what you’re up to,” Bhurkhay says.

Second, approach your partner.

There are no two ways about it: This is a difficult conversation to have. There are a few general rules for having difficult conversations that apply to this particular conversational topic: discuss it when you’re alone together, when distractions are minimal, and when you’re both relatively unstressed. Experts also suggest broaching difficult conversations with a partner by kicking off the conversation with an acknowledgment of the difficulty or awkwardness; they also advise avoiding language that sounds like an ultimatum or foregone conclusion.

For some, it might help to have a therapist facilitate the conversation, Burkhay says. A therapist can bring objectivity and make sure both sides get equal room to share their feelings. A therapist can also provide a set time and place to continue the conversation, since the discussion may not be resolved neatly after one talk.

Third, agree upon shared definitions and rules.

If your partner agrees to transition from monogamy to an open relationship, the critical conversation to have next is one that establishes what the new relationship looks like. “What does monogamy mean for each? What does love mean? What does polygamy mean?” Bhurkhay suggests couples ask themselves, together. “If we’re not associating faithfulness [and] loyalty, with love and sex, then probably a relationship can be more open.”

The crux of successfully transitioning from monogamy to an open relationship is agreeing to a shared definition of respect and loyalty; as one client puts it, Bhurkhay says, “We’re not going out because food is not available at home. We’re going out because we need variety.”

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Beyond that foundation, the definitions and rules will be different for every couple, she says. But she encourages couples to discuss hypothetical details before embarking on a newly open relationship, details like: whether they want to be able to discuss their outside relationships with each other; what they are each allowed to do with other partners; what the new definition of betrayal is; what to do if they’re out together and they run into one party’s sexual partner.

Ultimately, going from a monogamous partnership to an open relationship is about “being transparent with each other and honest about their feelings toward each other and to their other partners,” Bhurkhay says.

Fourth, be prepared for a no.

In a perfect relationship, everyone wants the same things. But most relationships aren’t perfect because the people involved in them aren’t perfect. Therefore, be prepared for your partner to have at the very least a different opinion.

“If I’m taking the freedom to talk to my partner, I must also be willing to take the consequences of that conversation,” Bhurkhay says.

While the decision to shift from monogamy to an open relationship is one that requires much discussion, if, in the end, each party has irreconcilable stances, each has to respect the other’s view. And each has to be prepared for that eventuality. “What is more important – the relationship I’m in, or my need for a polygamous relationship?” Burhkhay suggests asking one’s self.