Alright I was super young when I watched this so I don’t remember much about it. It may just be an episode from something. Here is what I remember it was probably about some superhero or people working on something advanced probably nanotechnology of some form (I am pretty sure the characters found something wrong with it that would affect the protagonist). The protagonist was trying to date a woman who was eventually revealed to be an antagonistic character she wore a mostly red costume with a mask (they may have gotten together but probably broke up when it was revealed she was a villain). The protagonist and the woman (antagonistic villain not sure if she was the main antagonist) were on some sort of date where they went swimming or doing something at a pier. I think it aired on cartoon network it may have had the marvel comics flag where it shows different characters being flipped through like pages on a comic book. This was probably before 2010 maybe around 2008. I was very young when I saw this and it may just be an episode from something any help whatsoever in finding this is appreciated.
It was animated