Boyfriend going cancun for two weeks?

My boyfriend of just over 17 months is going Cancun tonight for 2 weeks. We are quite close and see eachother quite regular but with a mix of seeing friends too! He is going with a group of 8 friends, of which 4 are also in relationships! Just want coping strategies /ideas to help me get through it - know its pathetic but im not used to this! Already feeling low