Well, mating was not a big deal for the Zerg race. The problem was that the Queen of Blades still had human emotions in her. She still had feelings for Captain Jim Raynor, an important figure among the humans. When it came to sex, she was completely unable to resist Sheyan, who possessed the genes of the ancient male Zerg, so Sheyan was just like a walking human genitalia to her. As long as he was at her side, acts of infidelity would frequently occur, and that was something she could not stand.
That was the truth behind the matter. Unfortunately, Sheyan would never know, so the tragic story of him being cast off as a pest by the Queen of Blades was doomed to become a permanent scar deep in his heart.
Fortunately, Sheyan knew he still had a lot of important matters to attend to, so he was not upset for too long. 99 out of every hundred men in the world had been cast off by a woman before anymore, so it was no big deal.