By the time the thought of a union even occurs to Lexa, she'd been seeing Clarke romantically for what seemed like years. Of course, she is aware of the rumours that spread through the streets of Polis- but none had ever been slanderous enough to make a situation out of. Most of the stories she hears are false accusations of Clarke's intentions with Lexa when they had started seeing each other, but those accusations had died down after the war.
The idea comes to Lexa when she wakes up before Clarke one morning, but rather than getting up and getting dressed like normal, she steals a moment to embrace the unusual serenity of the scene, and all she wants was to stay like that for the rest of her days. She'd always thought that when she did commit to uniting with someone, that it would be for political gain. When she'd first started seeing Clarke, she always thought she'd propose nonchalantly and explain that it would make them true equals, politically, and that they'd be able to rule side by side. However, their emotions both grew thicker and thicker with every day that had passed by, and then Lexa realized, that if she was going to unite with Clarke, she wanted it to be genuine.
As the months went by, their political alliance strengthened as the tensions between their people faded. Clarke grew to be Lexa's equal all on her own. The people of Polis admired Clarke- the golden princess of the sky, sent down from the stars to protect their Heda.
"Lex, you're staring," Clarke comments, drawing Lexa from her state of reflection. She smiles fondly at the nickname, like always. Ever since Clarke had started calling her 'Lex', she had been unable to maintain her stoic mask when she heard it.
"Forgive me, ai kwin," Lexa murmurs, propping herself up and pressing a gentle kiss to Clarke's cheek. Clarke raises her eyebrow.
"Ai kwin?" Clarke echoes, grinning mercilessly, and Lexa braces herself for whatever was about to come. "You only ever call me that when you're feeling especially affectionate. What's up?"
Lexa answers Clarke with a gentle kiss to her lips. She feels Clarke's hand wrap around the back of her neck, pulling her down closer against her. She responds with a gentle sound of surprise and feels Clarke smile against her lips.
"We have no schedule today," Lexa says, pulling away from the kiss just to move her body over Clarke's. "That's cause to celebrate, is it not?"
Clarke looks up at Lexa with adoring eyes and Lexa feels her heart tugging in her chest. She rolls off of Clarke and gets out of the bed. Immediately, Clarke sits up.
"What are you doing?"
Lexa kneels beside the bed, taking both of Clarke's hands in hers. Suddenly her chest feels too tight and she thinks for a moment that her ribs might crack, overwhelmed with her love for Clarke.
"Years ago, I swore fealty to you, Klark Kom Skaikru," Lexa says, brushing her thumbs over her Clarke's knuckles.
"Yes, I remember," Clarke replies breathlessly.
"I am here now, with a proposition to unite our two souls," Lexa continues, staring up at Clarke with unwavering eyes. "I believe your people call it marriage, which is horribly unpoetic, but if you wish for it, I will make it happen."
Clarke raises her eyebrows further, and from where Lexa sits on the ground, she can see the tears in her eyes. She hasn't thought of "love is weakness" in years, but now she understands. In this moment, she feels weakness in her knees, in her stomach, in the way her heart is hammering against her, in the way her lungs feel too small.
"What are these union ceremonies like?" Clarke asks, and Lexa can see her mind wandering. "Do I have to fight a blockade, single handedly? Or is it more like, we privately braid each other's hair and tell each other we'll be together forever, because if so, we've already done that."
"Clarke, please answer," Lexa pleads, her voice cracking slightly. She'd been holding her breath from the moment she knelt down beside the bed. Clarke's gaze returns to Lexa and she releases Lexa's hands. For a split second, Lexa's heart drops, but then Clarke's hands are on either side of her face, tenderly cupping her cheeks.
"I would be honoured to unite my soul with yours," Clarke says in a more serious tone that Lexa had seldom heard her use. "Though, I do think we were destined to meet. Our souls are already united. But I'll go through the ceremony anyways to keep up appearances, if you want me to."
"You've been talking amongst my people, haven't you?" Lexa asks, watching as Clarke joins her on the floor. She can't help but smile at the idea of Clarke being her soulmate- though that much was obvious.
"Perhaps," Clarke admits. "I just wanted to make sure they weren't dishonouring the good name of my love."
"You are very noble," Lexa agrees. Clarke leans in and kisses her, tangling her fingers into Lexa's thick hair. Lexa's arms wrapped around Clarke's neck.
"What made you ask now?" Clarke asks after they break apart, with Lexa leaning her forehead against Clarke's. "I was starting to think you never would."
"My spirit demanded it," Lexa explains. Clarke grins, her face alight with excitement. She knows that Clarke had a different understanding of the flame that was passed from Commander to Commander, but the only reality that Lexa knows is that she loves Clarke. And the past Commanders know it too.
But rather than chiding her for her weakness, finally, they accepted that when it came to Clarke, their love was strength.