My LTR of 4 years went on a trip out the country with a few friends for 5 days. On the second to last day, she posted a picture of herself at her table with one of her friends and two other guys.

I really want to question/address this, but I dont want to sound insecure. I dont think I should next her out of a 4 year relationship for this, but at the same time I want to figure out why she did this. Any suggestions?