My hubby only has this 1 female colleague and they have to work very closely in oil and gas industry. I cannot help to feel how they might get into affairs as the girl is very flirtatious. Being a woman myself I know what she's up to. I am super paranoid by all her msgs / actions. I am not sure if I can trust my hubby but I cannot trust that woman for sure althought she herself is married with kids. But goes drinking 3-4x a week for "entertainment". It's driving me insane. How can I prevent anything from happening?

I second about the talking to your Husband thing. I think that you should let him know your worries and concern when you are not feeling emotional about it or he will brush you off and not take you seriously. I understand that it sounds like the other woman is up to no good so maybe you can tell your Husband the things that you don't want him to do with her or just generally women. The fact is that there will be other female colleagues and clients who may seem to pose a threat in the future so I think it is best to work with the inner circle - your Husband.