Hes married and obviously an asshole. Ignore him as much as possible. Act like he doesnt exist and if he suggest anything (dating etc) tell him straight hes not your type and walk away. Dont show any interest at all-not even to be polite because men like him usually have such a big ego-they will take it the wrong way. Just ignore him, do your job, try to make friends with people your own age at work and do your own thing with them at lunch etc. He will soon get bored and leave you alone
"Don't ask a question if you can't handle the answer".