From my limited understanding of afib, it's impossible to say if you will go into afib again, I'm hoping you won't , as I'm sure other forum members, you and your husband are hoping as well. But you're far better off knowing that it may recur and receiving appropriate treatment. You're apparently already on medication to treat afib in addition to a blood thinner, the medication may be working as it's supposed to.
The following saying came to mind when I read your post. Sometimes we are better off knowing what we have or may have, even if it creates some anxiety, than not knowing what we have even if we're happy.
"A saying from the area of Chinese medicine would be appropriate to mention here: "One disease, long life; no disease, short life." In other words, those who know what's wrong with them and take care of themselves accordingly will tend to live a lot longer than those who consider themselves perfectly happy and neglect their weakness. So, in that sense at least, a Weakness of some sort can do you a big favor, if you acknowledge that it's there."