Hi My Boyfriend (28) And I (30) Are Together For

Hi
My boyfriend (28) and I (30) are together for a year, we went hiking and camping on a weekend with a group of professional hikers. Everything was fine until our tent got attacked by wild horses and destroyed the next day. I preferred to go back to the car and spend the night there (car was 2 hours away from camping area) and he came with me.
At the end of the road close to the car he shocked me saying we could have spent the night there, I could've slept in a girl's (2-person) tent and he could've slept in another girl's (2-Person) tent because it was an emergency or something.
I was really shocked, I think and feel it's not right for a committed man to do that but he doesn't accept it.
Could you help me if it's wrong or right and give me some reasons please?
What should I do in this case?
Just for your information, he has slept with a girl one of his friends but out of a relationship and it hurt my feelings. He thinks that was wrong but he never told me why he did it. He just says out of curiosity.

Thanks a lot!