Coffee means zilch to me. I'm a caffeine free diet Coke drinker. If I can't get that or a reasonable facsimile I will drink water or nada. My brother is a coffee addict but will
choose from his list of favorites. He hates Star _ ucks, use your imagination, with a passion. Says it tastes bitter & burnt. He likes Kona & a few others.
Im glad im not the only one! I get an energy drink once wk and take a lil sip of of it each day

Seriously, all that sneaking about pretending you don't know is going to catch you out. It almost always does. Eventually the person you work with will find out you know the man. Gossip, especially for something like this spreads like wildfire. You're already posting about here............
Do the right thing. If it makes life at work a little uncomfortable you will at least have the knowledge that you did do the right thing.
This is sort of my take plus how would you feel if someone knew someone you dated was not right and didn't say something? She probly does have the aforementioned rose colored glasses about him and it probly will make for a slightly uncomfortable situation so maybe wait a Little while, see if it fizzles out on its own? If not id approach her like "i dont want to make trouble between us but i dont want to see you in trouble either"