Wife staying out all night with singe girlfriends at a casino. All have rooms two girls sharing rooms. Wife and another girl have separate rooms. Calls this girls night out. Feel something is wrong.

How often do they have 'girl's night outs'?

Have you ever had reason to not trust her before?

Have you talked your wife about the rooms and your insecurities? Do they have understandable reasons?

Do they plan to have any alcoholic drinks? If so, then I applaud their getting rooms instead of driving home.

No

You need a lot more facts than you have before jumping to the conclusion she is cheating. For now you only have her word, so believe her if she has no history of lying, or cheating.

Ask her what's going on and tell her you are uncomfortable with the situation - be prepared to tell her why you are uncomfortable.

Need to give more information on the situation. It does not sound like a regular thing. Girls going out for a time at the casino. Is it the casino that bothers you or that you are not their to watch over the girlfriend. Is this a trust issue or control issue?