My boyfriend cheated on me while out in Vegas, and I forgave him.

My (30F) boyfriend (38M) got surprised with tickets to Vegas for his birthday by his best friend.

Last week, they jetted off, and I wished them well. I wanted them to have a great time, but I was not expecting this to happen.

So last night, my boyfriend told me that he and his best friend hooked up with these girls. I was devastated, and his reason was "Well, when in Vegas..." which upset me further.

Upon further discussion, he realised how messed up that sounded and apologised profusely. I decided to forgive him, but I can't shake off the feeling of when I see him next.

All I can think about is him with someone else, and it eats away at me. My question is, would you forgive someone in this situation? If yes, how do you work through it? How do you trust your SO after cheating scandals?

Any advice is appreciated, thank you.

Edit: Thank you for all the comments. I've read through them all, and took on the advice. I'll be talking to him in person next weekend, and I've decided to break things off with him.