When we met, she awkwardly mentioned that she had a male housemate. Nothing romantic, he had needed a place to live and had his own little suite setup in a separate area.
Later it turned out that he was horrifically jealous of my being around her, to the point that they would fight after I left. He started getting drunk a lot.
After like 4 months, she finally admitted that she had slept with him before we met and that he had drunkenly confessed his love for her just before we started dating.
I nope'd myself right the **** up out of that situation.