I've given it some thought and I don't think it's appropriate for me to be in a hot tub with other women.
Do you feel this way because you don't want your girlfriend to have any motive to be upset?
Yes, my girlfriend is such a high-strung person and I don't want to upset her by doing this.
It is very understandable to respect your partners wishes and avoid any conflicts. Avoiding any compromising situations is very proactive.
Okay, I'm not going to do it and I'm not going to look at my coworkers in a swimsuit as well.
Respecting the wishes of your partner, so long as you're okay with them, is proactive and respectful. She probably feels glad to have you as a partner and appreciates that you are mindful of her feelings and knows that you wouldn't put yourself in situations that could damage your relationship.