What does a birthmark in the shape of a keyhole mean?

>>; I have a birthmark on my "wedding ring" finger, that is in the shape of a keyhole and i was wondering if anyone could tell me what it means. I never really put much thought about it until my boyfriend told me that he had a heart-shaped birthmark on his hand so when i looked it up, i saw a ton of meanings for his mark. So Please someone shed some light on my little situation. Thank you xD