Not really, at least it's not to me. Now if he wanted to have sex with her especially in a swimsuit, then you could definitely call it perverted, albeit more as in swimsuit fetish. As it currently stands, he just wants to see her in a swimsuit and at the beach. So he's definitely more fueled by the thoughts of playing at the beach with her rather than perversion.If a boyfriend wants to see his girlfriend or a girlfriend wants to see her boyfriend in a swimsuit, is it really perverted?