I believe most parents, if they are honest with themselves, have wanted a break from being a parent. It's the hardest job anyone will have. It's 24/7/365 and lasts at least 18 years. I also believe that lots of folks have misgivings about roads not taken.
Is there a way you could take some time away from being a parent? A vacation without the kids maybe?
Are you in therapy? You could talk about how you are feeling with a therapist and look for some suggestions.