lol he was insecure for a moment that stupid doc, he was insecure because Nonami was gazing at her wedding invite with somewhat of an emotional expression.
No, Uzumi had a feeling of sadness when he saw Mami's wedding invite because it reminded him that he can't share that kind of happiness with his love because two men can't get married in this story's setting.
Why does Nonami said :" This love is too painful" when he saw wedding invitation of Mami?