Heidi,

You sound like a respectful and sensitive person in thinking about the person you love, Ryan, and his close friend. And it sounds like you are all intelligent and caring people. While it sounds like they have a close friendship, you and Ryan have a love relationship, and that is just as important if not more so. I think it is completely appropriate to express your needs in a situation like this, and asking the person you love and will marry to not go on a trip alone with another woman because it makes you uncomfortable is not unreasonable. Especially since you do not want them to separate completely. I know I would feel uncomfortable in such a situation.

Good luck, you deserve to be happy too.