OK, I have two things.
Problem with kid: His son is three years old and that's really, really young. Sometimes parents just kind of give up on controlling a child that is uncontrollable. Have you spoken with him about this? You may not have parenting rights to your child but if he's hurting your own kids, his father should know about it, and he should know why you're not going to get your kids together anymore.
Problem with text messages: He said he wouldn't do it again, that's the important part. So you disagree on privacy; as long as he's able to respect you that's what matters. Can I be honest? If you expect something to remain private, it's a really dumb idea to send it in a text message.
Re: the second thing
Oh, wow. I would definitely end it with him for the pictures incident. That's something that he should automatically know isn't right to do regardless of how long you've been dating. If you think you can teach him a lesson by having that talk with him/get an apology from him, and then move forward in the relationship, you are really naive. That incident indicates a deeper character and life perspective that is totally incompatible with you and the type of intimacy you're capable of having with someone. He isn't that someone. Other scenarios will play out that will be reminiscent of this situation. Don't waste your time to wait and see other issues crop up. This is the kind of thing that should put you at a distance from him to the point that you don't even feel any sort of codependency while telling him you aren't a match and are moving forward with your life.
Welcome to the board, Just_wanna_be_me ~
You're going to hate my answer.
You've only been in the relationship for four months, this is still the very early stages of it.
Oh I remember the age of 3 as being very difficult w/ my son.
"Son immediately whined and shook his body"
I guess I don't see the big deal.