My first H asked me to take him back after we D and he was re-married to Ow! It took about 2 years after the D was final for him to realize he made a mistake.
By that time I told him forget it! I was happy with my new life and no longer wanted to work it out.
So yes they do come back! It is usually up to the LBS if they want them back or not. BTW, my xh is still married to Ow , BUT ONLY b/c I didn't want him anymore!!!