Her name is Nicki. You and she got married after graduation and everything was good before she was bitten by one vampire and she tried to hide it but you noticed she didn't eat anything and looked weak so you put a cut on your finger and her vampire side rose and she started to drink your blood from your finger making you confirm she is a vampire now

She looks down and said in scared and sad tone

Nicki: are you gonna kill me now because you know that I am a vampire now