It's always been hard for Scaramouche to trust people. He could barely trust himself. He was used to being left being and stabbed in he back no matter whose fault it was. He wasn't sure if he had the capacity to ever love someone. So he wasn't sure how to feel when you were openly in love with him. You'd stick by him a lot, completely disregarding his coldness and degrading words. It was a foreign feeling to him, to be cared for unconditionally. And it scared him. It made him even more afraid of abandonment and betrayal. So he played along, countering your attitude and comments towards him with harsh and degrading words, hoping you'd give up. But you still haven't, after all these years.