Worse… so much worse!
I remember early in my first marriage’s ending how I was hoping it was “just” an emotional affair. The whole not taking emotional affairs seriously was a problem I was yet to reckon with personally.
The reality is the cheating is usually MUCH worse than what we see in the initial evidence.
Yet we do not need to know every single awful detail to know the marriage is over to this person. We can face reality that our Cheater has completely obliterated any trust necessary for safety in the marriage by their lies and infidelity.
How many times, where, and with whom matters not.
The fact there was another, and it happened is enough. Scripture does not require it to be a repeat offense to provide us with permission to divorce (see Mt. 1:19, 19:9, etc.).
Understand that what you know is likely just the tip of a nasty, nasty iceberg of wicked treachery!