Fake

They give us the same vib. There also about 2 guys that are always together and fight together they also have a boy love( shounen ai) element 

Although the art isn't anything alike and the most alike to this movie is going to be either Junjou Romantica or Sekai Ichi Hastukoi which are both by the same author, I thought it would be a good one to add. -Men who work together and fall in love -Heartbroken romance(Side character) -Both have a 'large mystery' to figure out -both a movie -'Uke characters' like and do good with kids -Both inlude stories about someone's child that is intremental in finding the resolution -Both have feelings for the other side but maybe aren't willing to accept it. And the one I appreciate the most- -Both couples are aware of the other's feelings and accept(in hatsukoi-grudingly)the advances. They don't fit under the same genre as Hatsukoi is stricktly a romance and Fake is a mystery but I feel like the romance in Fake fits nicely next to Hatsukoi's. They are just similar enough in several respects that I think that if one is enjoyed the other could also be(ane maybe even be liked more).  read more 

Both are Shounen-ai series with a lot of comedy where the main heroes are a team of detectives. 

A short anime about two grown-up men in love with each other going on a vacation together. There are some differences but it's similiar in many ways. 

Fake and Zetsuai both deal with the problems that arise from a romantic relationship between two men. Fake is light hearted with a thriller related plot while Zetsuai is much visceral and dark, fans of one should be interested in the other, though. 

Fake and Lesson XX revolve around the growing romantic entanglement of two male leads. Fake has plenty of comedy and is action-packed, while Lesson XX can be described as shounen-ai, slice of life, and is spiced with romance. Both deal with the conflicts of same gender relationships and the occasionally thin line between lust and love.  

These OVAs cover the same ground in that they are fairly humorous takes on shounen-ai romance. Plot-wise they are not similiar, Fake's plot includes a murder investigation while Gravitation deals with the music business; but anyone who enjoyed the relationship between characters and the wacky comedy of one is bound to enjoy the other.