OP only mentioned him cheating on his wife, so my comment was related to that: his infidelity to his wife

The entire scandal is a scandal to be sure. That he cheated on his wife with an intelligence operative and whatever happened beyond that is a problem and needs to be investigated and dealt with

But this thread was about him cheating on his wife full stop. He could have cheated with anyone else and it would not have been a problem. The cheating wasn't the problem, it was who he cheated with and what happened downstream

The cheating is a problem because it opens him up to blackmail and coercion. Even if he didn’t cheat with a spy, a spy could have used that as leverage if discovered.