Author's Notes: Written for the February 1st Prompt of the Day on Hogwarts Online – "Temptations".
"You may kiss the bride."
The words made sheer joy well in Rodolphus's heart. The bride. Finally married. He had waited for this for so long. Bellatrix, standing just before him, smirked letting him lift her veil and leaning towards him, laying a light, tantalizing kiss on his lips. He felt his body respond, his breath quicken automatically, though she barely touched him. Bellatrix awoke this passion in him every time she so much as looked at him, and it did little good to try to ignore it.
But there was something else he could not ignore, and that was the look of astonished shock upon Narcissa's face. He saw her out of the corner of his eye, decked in her pearly silver bridesmaid's dress, holding her bouquet, and looking as though she were about to burst into tears. Rodolphus felt a twinge of guilt in spite of himself, but he quickly pushed it away, dragging his eyes back at his wife.
There was polite applause from the congregation, many of them standing up to congratulate the newly married couple. Andromeda flew forward to embrace her sister, and Rodolphus saw Narcissa slipping away, slinking through the crowds and out the door.
"Would you excuse me a moment, love?" he asked Bellatrix softly, pushing Andromeda aside to whisper in his bride's ear. She nodded, already more interested in the attention being lavished upon her than in Rodolphus.
He smiled and nodded at people who tried to offer him congratulations as he made his way out of the sanctuary. Rabastan tried to follow, to talk to him, but he brushed him off, telling him he needed to be alone for a few minutes.
Once outside the sanctuary, closing the doors to muffle the excitement within, Rodolphus could hear quiet sobbing from the coatroom. He pushed the door open gently, and knelt down beside Narcissa, who was on the ground, crying into her hands.
She lifted her head. Eye makeup had run down her pale cheeks, and she sniffed. "Rodolphus…"
"Cissa, don't cry," he told her, taking his handkerchief and wiping her face gently. "Please don't."
"How can I not?" she demanded. "You- you married her!"
"You knew I would."
"I thought you were going to leave her," Narcissa whispered. "I thought– right until you said 'I do'– you were going to leave her…"
"I couldn't. We were already at the alter."
"She doesn't love you, you know!" Narcissa's voice dripped with spite. "She's in love with someone else!"
The words stung, but Rodolphus did not let that show in his face. "It doesn't matter. I love her."
"You said you loved me!"
"I was wrong."
Narcissa let out another sob, burying her face in his handkerchief. "But I love you!"
"I know, Cissa, and I'm sorry, but…"
She raised her head again, her lower lip trembling. "But what I want doesn't matter? That I love you doesn't matter?"
"Don't talk like that…"
"How am I supposed to talk? Am I just supposed to say that since I love you so much, I'll be glad you're happy when you're married to my sister?"
She closed her eyes for a moment, then opened them, rising up onto her knees and knotting one hand in Rodolphus's hair, kissing him deeply. Her kiss was far more passionate than Bellatrix's – and all the more so because Narcissa so rarely displayed lust – but Rodolphus could not bring himself to enjoy it. She snaked her hand down to the front of his trousers, stroking him through the fabric, and pulled her head back, her eyes half-closed.
"It doesn't matter…" she whispered, her hand gentle and steady on him. "We can still be together. You're married to Bellatrix, but you can still have me, I'll still let you have me…" She let go of him to tug down her strapless dress over her chest, showing off her small, firm breasts. "Look at me…" she whispered.
Rodolphus did look. She was beautiful, yes, and so tempting, but she was not Bellatrix, and she never could be.
"Don't you want me, Rodolphus?" Narcissa asked, her voice rising again, high and almost shrill. "Don't you want to have me? You could! I am yours forever…"
For just a moment, Rodolphus wanted to. The temptation was almost unbearable – Narcissa was young, beautiful, sweet, she would be faithful while Bellatrix would not…
But he couldn't. Narcissa was everything he should have wanted, but Bellatrix… Bellatrix was more. Bellatrix struck something deep inside him that made him mad for her. And if he took Narcissa, if he let himself ruin his marriage by carrying on an affair Narcissa, he would spend his life wishing for what he would imagine could have been if he had only been faithful.
"I can't," he whispered. "I can't."