Look.. you're not being unreasonable in that it's normal to worry if someone has broken your trust, but I do wonder whether you can really ever move past it.
The reason I ask is because you say the date is the same. So what, do you have a diary of the dates he cheated on you, and "Cheat-aversary" dates? That's a little bit weird. It doesn't matter what the date is, so I don't know what you mentioned that.
It sounds to me like you were incredibly upset and traumatised by the incident, which is fair enough, but unless you're willing to wipe the slate clean and start again with absolute trust, there is no point in being in this relationship. You will wind yourself up with thoughts of what might be going on, and he will be getting annoyed that he's missing out on things.
Incidentally, cheating can occur anywhere, any time. There's no point fixating on parties and nights out. You can meet someone anywhere and cheat, and even if he doesn't seem to be going anywhere there's always emotional cheating, or cheating during work hours. You can't try to control him like this, you will end up hurting yourself.
If someone wants to cheat, they will find a way. If you want to maintain a long term relationship with this man, the only way is to trust him not to cheat of his own choice, not because you're taking away the opportunity.