how do u do this?

so i'm new to this single mom life.. i do not want no contact or seeing my baby's father at all. he took away everything from me(car, stress,etc)... and he doesnt help me at all with his children no money or anything.. i buy everything .. we ended things a month ago.. his mom has been texting me acting like nothing is happening asking if she can see the kids.. i dont even want to see her either cuz shes supports his deadbeat ass .. she's a horrible mother she raised a cheater narrraist lying ass son. they don't deserve to see the kids at all. they took away my mental health ,my sanity .. how do yall single moms do it when the father wants to be with the kids ? or see them or the family ? how do u hand over the kids without seeing him or their family? impossible ....🤦🏻‍♀️ my kids are 3 years old and 1 years old. they are small and don't even talk yet