Hi Lost in my Thoughts,
I'm so glad you got to the bottom of things but I'm not glad for the betrayal and hurt you must feel. It's a massive shock to the system finding out a partner has been cheating in the relationship and he had plans to continue by the sounds of things; " they were going to meet up again on a date".
Your suspicions were right just like mine were when I felt that my partner was cheating on me.
I guess the next qtn is what's your next step? Are you willing to work through all this with your partner, get him help and continue the relationship, or go your separate ways?
If he's willing to get help from a professional like a psychologist I think that would be a really good step. I feel he owes this to you.
My ex partner didn't get any help and continues to be a womanizer, even now that he's married with kids.
They need to be held accountable.