Going home is actually an option, but will probably not be used.
The reason is cardiovascular. With the weaker gravity, you will have a weakened blood circulatory system. Low gravity functions much as long term bed rest does. You'd need literally years of physical therapy on return.
Mr. Kelly needed prolonged therapy after only around a year in Space. There are also effects on vision and hearing and bone growth. All can be remediated, but it's a pain to do so.
But the rockets that take you to mars will be coming back to get the next load of potential colonists, so yes, you can go home again. But you probably won't want to.
Most retirees like to stay close to the Kids after all.
Why work to build a large city then abandon it to complete strangers?