A few year ago I tried looking for a cabin mate on this site. Ended up finding a mate from the 2nd party site of the trip I was going on.
We emailed and spoke on the phone. Younger girl. Professed to be mature. The agreement was that we would not be attached at the hip.
The cabin experience itself was fine. But uniquely, she drove me crazy with a fantasy she had about marrying one of the musicians on the music cruise we were on. She felt is was her fate. Which is fine as long as I'm kept out of the obsession, but she was unable to do that.
Needless to say I've now booked a single cabin. I still love people and think everyone deserves an opportunities. We're all human. I'm a perfect example of imperfection! But vacationing is a luxury I work hard for, and now prefer to 'turn in' at night on a cruise in peace. and awake to meet many lovely people on the ship.
Communicate with your new cabin mate. but there are no guarantees.