If this is a regular thing, attraction will definitely occur at some point or another. Now we can debate whether or not it's usually the guy developing attraction for the woman or vice versa but attraction will definitely develop at some point given enough time. Is this a one time work thing or is this a once a week thing? Is this a voluntary, non-work required function or is this required by work? A work function is one thing and quite honestly, involves at least a few people, not usually one on one. A personal function of hanging out with someone of the opposite sex, including alcohol or the possibility of alcohol on a regular basis is inevitably going to lead to some type of attraction at some point. Imagine you've had rough patch with your boyfriend, you're meeting this other guy on a regular basis where the atmosphere is light, fun, breezy, perhaps even somewhat romantic (fancy restaurant, intimate bar setting) and includes alcohol. Sounds like the recipe for a drunken one night stand right?
I know, I know, relax, chill, blah, blah, blah. It is almost always the guy who gives up more to be in a relationship than the girl. Finances, circle of friends, whatever. A guy in a relationship hanging out with his circle of friends on a regular basis? He's a man child who needs to grow up. A woman in a relationship hanging out with her friends, guy and girl? She's letting off steam, she needs this, blah, blah, blah.