My wife wants to go on a 17-day European trip but I don't want her to.
Why don't you want your wife to go on a euro trip?
I feel that she can't handle alcohol well.
I can see you are concerned about her drinking too much and something happening to her but she would be upset if you told her what to do. It would be good to discuss your concerns with her instead.
She's a liability and I don't want anything to happen to her or herself.
I can see that you really don't want anything bad to happen to her but she might go in spite of you if you tell her she can't go. You should really talk to her about so that she can ease your fears.