Please lah. You watch too many movies already. Office affairs in big MNC companies are so common in senior management. It's all mostly voluntary (vs so-called sexual harassment type).
Affections and feelings for each other grow because they spend time together doing the same projects or are of the same wavelength in office politics.
Some with better self control resisted. But mostly, when an "edible" can eat don't waste type throw herself at a man, most likely the man will eat.
From thereon, it's about hiding from being found out by spouses, colleagues and friends. The better rendezvous locations will be outside of Singapore where they can show their affections publicly without fear of being spotted.
If both the man and woman are married, generally all will be fine because it's not in anyone's interest to break their existing marriages.
The problem is usually when the man is married and the woman is still young and single. The woman may be ok with being the third party when the affair first started. But as time passes on, she realises that she wouldn't be able to handle this man having a wife in the long run. Then that's when all sort of problems start to brew leading to exposure, etc etc.