My boyfriend of 2 yrs wants to go on a road trip with his female. Is it ok that I am upset?

She is a platonic friend that I met once briefly. I wish I was cool with it but I just feel incredibly uncomfortable. He also planned this trip while he was upset with me. Again, I wish I just didn't care and could be cool with it but I don't know if I have the capacity to handle this and it is causing me so much stress that I may just break up with my wonderful guy.