How old is your child? Can he or will he sit in front of a judge and affirm the spankings?
I do "spank" my children from time to time..I think I may have smacked their butts a total of 4 times since birth. It don't work most times so I figured why bother, it upsets me more then it does them. I just take away what they love i.e. DSI, TV, fav. toy. I had my mouth smacked from time to time for sass mouthing. LOL i still have a sassy mouth so it didn't work..I don't think a spanking is wrong unless it means that you ( the parent) have lost control. Does you ex lose control or is it the only way he corrects behavior? You know the answer to that like you said you were the buffer at one point. DO NOT make it out to be that he is abusive. A judge will ask you why you didn't file this from the beginning. He/She will think that you are only trying to get ex into trouble. When you do file, file in a way that it is sheerly out of concern for child's well being when with Dad. Does he (ex) have anger issues? Is your son acting different when he comes home? Dot all your "i"s and cross all your "t"s before you file. The judge I had would have laughed in my face, but then she has done that from the start. Be prepared to take the classes yourself. Your ex will turn this on you and try to make you look like a fool.

This is part of my declaration to the judge dealing with my requesty for parenting classes....I changed names to STBX and son and older son...

I am asking that STBX is required to take parenting classes in order to have visitation with our son, ______. I feel that STBX has problems with communication and has spanked our son numerous times out of anger for things that could have been solved with communicating. Instead of redirecting or giving him choices, STBX would spank him uncontrollably when STBX got angry. When STBX was living with us, I would be the buffer between him and son. When an incident would arise, I would tell him that spanking out of anger only teaches fear. I am worried that this is making son not trust him, fear him and causing problems for their relationship. I started to notice son having complete meltdowns when STBX would watch him. These meltdowns would happen frequently with son ending up inconsolable then being spanked hard for being so upset but continuing to be inconsolable after being spanked. Since STBX has left our home, son has not had any incidents where he is inconsolable. I would like son to have a healthy, nurturing relationship with his father. I know that it is greatly important that there is a strong bond between both parents and their children and want to see this strong bond between STBX and son. I feel strongly that parenting classes will help to achieve this relationship. Without tools for better parenting skills, I am fearful for our son. He is a sweet and loving child. STBX reverts to spanking him out of anger quickly and without communication as to why he is doing so. I see this as a fear tactic that is having negative effects that will continue to be destructive to our child's physical and emotional well being. As for our teenage boy, When I was pregnant with son in 2002, I witnessed STBX get into an argument with older son and hit older son on the head with a pan in our kitchen. I was so shocked that I yelled at him to 'never touch my child again'. He didn't touch older son again until older son became a teenager and we started to have difficulties with arguing. STBX started to push and shove older son into his room on a regular basis. In May 2010, STBX forced older son onto his bed and pinned him down grabbing at his face. He said that he was holding older son's face for him to look at him. Older son said he was in fear for his life and said that he looked into STBX's eyes and saw an 'extremely unstable person.' I have also told STBX not to touch older son on numerous occasions. I told him in June2010 that I could tell he didn't love him anymore and if he wasn't willing to reconnect with him and love him then do not touch him, period. I told him to use words to solve issues when they arise, but still STBX has physically pushed, shoved, and caused older son to fall backwards during arguments. The last altercation in September was witnessed by a friend who was staying with us at the time. STBX rushed atolder son and put his hands on older son's neck while shoving him outside. I could tell that STBX was disconnected emotionally from older son and told him not to touch him but he did it anyway. I am afraid that without learning skills for parenting, STBX will revert to physical disciplinary actions that will damage our child emotionally and/or physically. I feel that STBX needs tools for communicating with our child so that he can better solve problems and situations when they arise rather then resorting to violence. I request that in order for Soren to have visitation, he seeks parental counseling for the best interest of our child.
As well, I have been seeking counseling for son and myself to give us tools to get through this divorce. We will be seeing a counselor through Shasta Mental Health in December.

Letter is good. I think I would take some of your ( I feel) emotion out of it. "I'm concerned he won't have a relationship with his father" kind of stuff. Leave that to Dad. Just stick with the facts. Is your son's counselor able to back up your feelings? Is he/she concerned about how child acts? Ask your counselor to talk to your child about how he feels when Dad gets angry and see if counselor will back you up. Your oldest is a teen, correct? Will he go in front of a judge and tell about Dad's behavior? Start documentation on how your child is when he comes home from Dad's house. Best of Luck your ex sounds like an ass.