5 week vacation planned in 2 weeks but we have just broken up

My boyfriend kissed a colleague on a work trip about a month ago. I was so devastated when I first found out and said I wanted to break up, but have since communicated that I wanted to make things work. He says he has done irreparable damage to the relationship and it’s killing him that he has done this and that I deserve better. I’m broken and can’t imagine my life without him but he thinks it will be painful for me for us to stay together.

We have a 5 week vacation planned and leave in 2 weeks. We have decided to go because i will never get 5 weeks off in my career again (it’s a one off my company offers) and we have spent a lot of money booking hotels, flights, etc. we have also discussed and think it might be a nice way to bookend the relationship. In terms of communication, we have decided to just discuss travel logistics.

Am I making a huge mistake if i go? I don’t want to regret not taking the time off because he messed up, but am I just delaying the inevitable? Part of me hopes the time together will remind him how great we are, but I’m worried it will be horrible.