If my girlfriend went on a cruise or traveling without me, I’d simply assume that we’re already done and end the relationship. Healthy people in healthy relationships travel together, they wouldn’t feel the need to get away from each other for a bit or “let loose.” (why can’t she let loose with me?)
I know a girl who traveled for three months while she had a boyfriend. He ended it half way through. Figured she had to be cheating on him while he was gone and wanted to get in on that action. He cheated on her while she was gone before he broke up with her. But the passion was already gone in their relationship long before she left.
It’s absurdly simple once you think about it. Who wants to escape a relationship that’s working?
Let your girlfriend go. She’s just being nice to you and hates confrontation, that’s why she hasn’t already.