There are a lot of stereotyoes that men usually live in dark flats with heavy wooden furniture. But it actuallt depends on the character and a lifestyle of an exact person. And you can`t judge or predict the design of person`s living place. 

Guys tend to feel more comfortable with a palette of white, gray and black. Think about adding color with a piece of artwork or an accessory rather than a big, splashy red wall or bright bedding. And be sure to balance out the neutrals. 

But, anyway, you should choose your design including your own wishes and prefeties. To take a look at all possible cute and manly designs for your estate I recommend you to take a look at Spotless Agency portfolio https://www.spotlessagency.com/portfolio - there you will find a plenty of option how to design your flat.