Yes. I genuinely believe Sue cheating on Reed without any outside factors involved (mind control or possession or skulls or whatever) will cause irreparable harm.
Sort of like how Hank slapping Jan caused irreparable harm to their marriage. From an objective standpoint Hank slapping Jan is not the worst thing we've seen in comics. But because husbands hitting their wives is a real life thing, it causes more harm than making clones of your friends or imprisoning them in the negative zone.
If you're marvel and you're involving the characters in real life domestic issues, you're potentially making a statement about them regardless of whether you intend to do so or not. It's part of the reason why Spiderman's marriage can't be a simple divource... it needed more of a fantasy/sci-fi spin on it so that Spider-Man and Mary Jane aren't becoming some sort of proponents for any sort of real life relationship issues.
If they wanted to really end Reed and Sue's marriage that's another matter entirely. But if they're just playing around with the relationship a bit, then you likely need to be a whole lot more careful about how you handle it.