It is not that uncommon for exes to remarry. Sometimes it is just a matter of two people maturing and trying again, so yes, it is possible for the ex husband and ex wife to rekindle a better relationship together. By 51 years of age hopefully the two people involved have learned something about how to work on a relationship and communication is the most important tool a couple can have. Take at least a half an hour or more a day to ask each other how their day went; talk about any problems and try to come to a solution as best you can and know you can talk to each other about anything. Once a person has mastered good communication skills the relationship is much healthier. It wise for the two exes to take it slow and easy to be sure that each of them have matured and they can see good changes in each other before contemplating marriage the second time around.