My Boyfriend Enjoys Torturing Animals?

We were at the park today and his dog caught a rat and I yelled at him to drop it and the rat was unharmed but really scared and was like shivering still and I was too scared to go close to it but my BF went and he wasn't scared at all and he was like smiling and happy and started pushing it around with his foot asking if it's alright and said it's cute and just stood still for a second and outta no where he lifts his leg up all the way and curb stomps the poor thing and keeps stomping on it until it died. It looked in soooo much pain and was making weird noises and I was yelling at him to cut it out but he didn't stop until there was just a bloody pulp of guts and his shoe and the bottom of his jean were covered in blood. I almost threw up and asked him what the hell was that when he was done and he told me "don't be such a pansy, it's just a stupid wild animal, no one cares whether it lives or dies." I'm really disturbed by it, why did he kill the poor thing for no reason?:(