I don't think my husband will return under the current circumstances but I feel he may try to return if he gets burned in enough relationships and dates enough hot 20 year olds to realize it's not the fantasy life he expected. If he reaches a point in the future where he realizes his life with our daughter and I is better than running around with whichever 20 year old he picks up at a bar then he may try to return, but that seems like a good couple of years from now.
Reading this, it sounds to me like you're willing to let him have his cake, and when he's been through all the other, preferable, options, allow him back to work on your marriage. You're not the option of last resort! You deserve to have someone who knows your worth! I'm pretty sure as time goes by, you'll begin to see that HE is not worthy of YOU. When that happens, you will be ready to move on.
And like KitCat said, focus on the positives. You've come so far.
M:23 T:26 Me:53, Wife: 60 S:18 D:16 filed 7/16 W moved out 4/28/17