Douchecanoe

A person (in this case a dude) who's douchey-ness cannot be drowned out by a fake personality. A douchecanoe typically is condescending to their significant other, flirts with other girls, and has a huge ego. Not the type of people you want to be surrounded by, but once you are wrapped up with a douchecannoe, it's hard to get out. Douchecanoes are often manipulative and try to convince you their mistakes are your fault. If you are with one, good luck.

Guy- Did you hear how he broke up with her?
Girl- Yeah, didn't he end things in the car right after a school dance while she was still in her dress?
Guy-That's what I heard. What a total douchecanoe.