*Yes at the the beginning there was a mad rush of finding yourself with someone, doing something you could never have imagined you would ever do. A madness about it.
Now, it's become part of the everyday part of living and you know this is it - there is what there is now, no more...*
Sorry to be a cold bucket of water here, but that was always going to the situation whether you got together or not.
Those sparks? That drama? That "need him in my life!" "couldn't stop myself" etc?
It never lasts. Actually, count yourself lucky. 'Cos the fact you won't leave your partners means you get to squeeze every last bit of illicit thrill and "madness" out of each other that you can.
You two actually getting together? It all becoming "normal"? Not so much.
Stats don't lie. Most people who get together with an affair partner don't last because it only works whilst its a fantasy and another partner is in place to handle the mundane/adult areas of life with you (so you two can keep things strictly sixth-form poetry). It's something ridiculous like 90% of affair-born marriages fall apart.
I count past relationships of my own in that. I learned my lesson.
So, yeah "enjoy" what you got. Any other option, the fire dies quicker. Of course, as with pretty much all these affairs, yourpartners probably will find out at some point. It's pretty inevitable. So brace yourself for that. On the plus side - it'll be plenty more madness!