Co-worker keeps asking for sex

My co-woken is 30 something and he has 8 kids me I’m 19 with a son. The guy is cool and everything but he keeps asking me can he touch my butt or he’ll walk behind me and touch it and it’s getting annoying. He’s always asking me can he hit it from the back one time or can he eat my pussy. He says a lot of sexual things to me and im tired of it, at this point i don’t even like working. He has a wife and he has her name tatted on his ring finger and she picks him up from work everyday and when she gets there his whole attitude changes.

They have argued a lot in the past to a point she said she wasn’t going to pick up from work so the manager had to take him home but she always goes back to him, he has had sex with 2 past workers but I refuse to have sex with him and it’s like the more i refuse the worse it gets.

He’s cool and everything and is very helpful at work but like i tell him all the time i do not want to have sex with him.

I don’t know what to do because at this job ik the general manager will never fire him.

He wouldn’t even talk about the issue he’ll just ignore it so that’s why I’ve been dealing with it.