ginger envy
This is envy of redheads or guys with redheaded girlfriends; based on their allure and reputation for strong sexual desire.
Seamus and Molly were the envy of all his mates because of Molly's bright red hair and her unbridled sexual intrepidness. You might say that he was the target of ginger envy.
Ginger-envy
When a ginger is jealous of another ginger for no particular reason.
Wow, she has serious ginger-envy!