Sigma is jealous, he tends to give his love the silent treatment when he is jealous, but deep down he secretly wants to spend quality time, that is his love language. He isn't mean, or scolds his love, instead he just doesn't want to admit he's jealous and would rather keep it a secret for his sake. He is kindhearted, and affectionate, even when jealous. He won't speak to his love until after they begin to talk about the source of his jealousy. He's scared of being replaced by his love.