this could turn into disaster for you. but since you're asking...
does he flirt with you? does he talk about his wife around you? how would you feel if his marriage broke up after you had sex with him?
i think these are questions you need to ask yourself to decide if you want to proceed further,
id go with the less direct route. I would ask him for advice on a dating situation and see what he says. tell him that there is a guy that you're dying to sleep with and that you feel horrible cause you just want to have sex with him.
if he is willing to talk to you then id be like I feel comfortable talking to you because you're an older man and I think you'd have a good opinion for me but if you don't want to discuss it with me then we can just drop it.
if he won't talk with you about it there is a clue to move on. if he does tell him how you want the guy and how you want him to take you. tell him that its been awhile since you got laid good and you need it...if it hasn't lie to him.
if he makes advances or flirts then react to it. but id pick a early point in the conversation to move the conversation outside of work.
once you get him outside of work id make it a really hot conversation. sit at a bar where you can see his pants to see if he has a bulge in his pants. once you have him turned on ask him if he would take you to a motel and f*** you. tell him that you don't want his number or anything, make it clear you don't want to screw up his marriage. tell him that you're in the mood and need it and if he wants you that you're all his. tell him he can take you up on your offer now or later.
if he wants to fire you for this advance, ask for a transfer or beg him to term you as if you quit by just leaving or moving since you're totally embarrased and contrite.
you need to decide if getting f***ed by this guy is worth losing this job. you may decide that you want to f*** another guy somewhere else by just asking. say you see a server for instance and think he is cute. give the server you're number and see if he'll take you to dinner...then make sure he takes you home and f***s you.
what state are you from?