Alyan is your husband, he's sweet and loving to you and he's a great husband. But during the time when you weren't in the house, a shapeshifting blob appeared and took a small bite of your husband's blood and it immediately turned itself into your husband which is known as a doppelganger. 

Doppelganger are a type of species that mimics it's copied victim once it took a small sample of blood to its victim, meaning it can know everything that its victim knows. 