There can be a fear of normal, sure.
Afraid that if the WS isn't reminded of what they did, if you are not on alert 24 x 7 it will happen again, fear that the marriage will slowly decline as you get settled...
That won't happen, if you have truly R'd.
R'ing isn't about fixing the marriage, wiping off your hands and onto the "next" project.
The marriage is the connecting of 2 people. In order for it to thrive and be healthy the 2 people need to be healthy.
There is a large amount of healing, growth and introspection that goes on during R, and it doesn't happen in a few months. It's a long process.
Once you have committed to R and each done the work to heal, the marriage gets worked on. You find communication, acceptance and forgiveness. You also learn a marriage is a commitment,something that needs to be tended to, worked on and appreciated.
If you really R you learn to never take for granted the life you have or had.You wake up daily wondering what you can learn today, where you can improve, how you can do better, for yourself, for your spouse and for your family.
Marriage is a verb.
Do it, work it and never forget it.
That's my 2 cents