The Little Black Bestiary: The Salted Cookies of Carthaginia

This is a short slice-of-life visual novel about an average guy spending an afternoon hanging out with his girlfriend Carthaginia, [former] Eternal Dread Empress of Samhain, [retired] Nation-eater, and Immortal Lich, presently on parole for charges of attempted inter-dimensional conquest, raising a skeleton army without a permit, and disturbing the peace... he did always have a thing for powerful, assertive, older women.

Since Carthaginia's nation conquering days seem to be behind her, you'll just be watching TV with her, helping her with tech support, and ahem 'getting busy.'