In Tales of the Frog Princess a vampire named Garrid falls in love with a real bat named Li'l while she's time traveling, but Li'l goes back to her own time. Garrid, realizing he loves her, waits for her. They get married and have children. It's mentioned that Garrid spent hundreds of years trying to find her. This is all very sweet until you realize: Li'l will almost certainly die before Garrid, and we don't know if his half-vampire children will live forever like full vampires. If they don't, Garrid will end up alone again, but this time forever.
Unless he turns her into a vampire. If that's possible.