@Happylife1416,
from experience, I have to tell you....
all affairs are fantasy. there isn't much reality in it, b/c all you're focusing on is the chemistry. which leads to sex which leads to emotions...
you may be happy with your husband, but there's something definitely missing. Not in a permanent way, but something that needs to be looked into, b/c this guy obviously gave you a fix that you aren't getting or getting enough in your marriage. it doesn't mean your marriage is doomed, but unless you figure out what it is and work with your hub to figure this out, you'll end up being dissatisfied or worse subject to being vulnerable to the next guy who gives you this fix.
good luck to you, though i'm hoping by now, you're over it and moved well past.