Well, you have only 12 ancestors you cannot expect finding so many connections there.
Cutting your ex and his tree will be a selfish brutal action against your children. Even if it is your ex family for you it is real family for them.
To fix this you need to start working on your tree to add more profiles and connections, - it does not happen by itself unless another family member or collaborator help you.
Start with your mother and your fathers mother - they are both without parents, - add them and you might get lucky to get a blue duplicate marker telling that someone have more on this line and save you from doing more research and can just merge the duplicates to get a connection.
I have plenty of family on there. A pathway thru an ex is not biological and should not be there. As for your opinion about cutting my ex-my children and I were added on there by someone with good intentions but even they as well as my kids cut their father out long ago. Before you pass judgment you should consider what you say and think about others when you don't know the situation.