"Sigyn, the Goddess of Fidelity, Loki’s faithful wife. She was meant to marry a warrior but Loki wanted her so he killed him and married Sigyn. She was always loyal to him, even when he pushed her away. The only myth that really includes her is when Loki is being punished by being tied down under a snake that drops poison from its fangs onto Loki, but Sigyn sits beside him and catches the poison in a bowl to save her husband whom she loves." << OMGT
Vine redraw thing by Nanihoo on DeviantArt - The one and only thing I do not like about this artist, is that she wants Loki to bow before her. She puts herself above him. If you look at much of her drawings, you would be able to make that inference. Loki would "NEVER" do that! Not even to his beloved wife that he cherishes so much! It's not in his nature.
Headcanon: Sigyn, Loki’s presumed dead wife, is actually one of the many scientists working for Tony’s company. Unfortunately her cover is blown when Steve runs into her, as he remembers seeing her work with agent Carter in the ‘40s.