My BF hates my one piece bathing suits?

Im fit and have a flat stomach but love wearing one pieces swimming and even under my clothes in the summer, but my BF is grossed out by them. Like when we're in the pool or waterpark and Im adjusting my suit he always looks at the suit funny when it does the slurpy thing or when u pull it out and its like SSHHLUPP :-P...Then when we cuddle and he puts his hand on my stomach he's like eww and pinches out my suit. He didnt think much of it until he heard my friends talking about how one pieces stick to you the whole time. Girls: are one pieces really that gross u think? Would u give up wearing them for a 2 pieces?