Even in the (very unlikely) event Melania was planning to divorce Trump, now, she can’t, not after that thrown gauntlet by Stormy, because so much attention will be focused on that topic.
If such plans exist in the back of her mind, it won’t be done in any obvious way anytime before November at earliest. When you are an internationally known public figure, you, by necessity, forfeit a large portion of your personal privacy. Not all of it, but a great deal.
I hope they weather this storm. I pray for Trump and his family every day.