Shameful behavior from shameful people. I hope that you and your son have a better day tomorrow. Your ex will be the talk of the town, he will regret all of this someday. Not soon enough, but it does happen.
In the meanwhile, take care of you and your son. You did not do anything to deserve this treatment but you must do something to make yourself feel better. Take a walk, call a friend or IC, have a good cry but do something for you...
