This is probably off topic on this site...
I am sorry I can't read all, the Google translation don't recognize your text
You are probably a good looking guy, or/and nice person. Take it as a compliment.
But you ask about advice..
Talk with him!
If you know he is gay, he is probably openly so. This make things easy, because you don't have to discuss his being gay. At a quiet moment, bring him a coffee, and discuss the problem. No fight, just quiet talk.
Tell him that you don't like his advances and comments.
I wonder how you would react if it was a female co-worker, constantly leaning over showing her breasts?
I just tell you that his being gay has little to do with it, but his attitude.
Good luck, and a happy new year!