How can I find out if someone is related to me if I don't know much about my family tree?

[Amanda Michael]

So I am seeing this guy that I have a ridiculous amount in common. So much so that it creeps me out. We have the same freakin birthday. And the night before I went out with him I was trying to show my mom what he looked like so I pulled up his facebook profile picture and she looks at me and says hey you guys kinda look a like. I didn't think anything of it at the time but after going out with him I feel like he is the male version of me. So that is what got me to thinking what if we are related??? I have a huge portion of my family that I know nothing about. I really like this guy but I don't want to be dating my 3rd cousin????HELP
And how do you propose I ask him to take a DNA test mr.shutuupaface? Hey I really like you but I just wanna make sure your not my brother from another mother can I have a piece of your hair??? lol

[shutuppauface]

DNA test.

EDIT:
You asked a question, I answered it. How you go about implementing the input it is not my concern.

[john]

penis him on chat roullete