This post is coming across as if you still want to be with him, and don't want to stop reaping the benefits and resources he's providing you with. Phone calls, support, driving you to work, visits, time spent together, etc...
You allegedly have moved on..but
You wrote about how he's trying to be more respectful towards the dynamics and his relationship by trying to set boundaries....
but you aren't even doing so in your new relationship. You aren't acting appropriately and being respectful of this new person and relationship.
You're too invested in his personal life. I feel like he needs to go to court to solidify legally his rights and visits as a parent.
He is frightened that you will stop him from seeing his child because you have done so in the past for perhaps petty reasons ...when he gets in relationships and stop doing for you....you perhaps become bitter, threatening and jealous..and use the child as a means to stay in and control him.
He is allowed and entitled to move on. You are too. This is sounding like you haven't moved on. Everything is fine and you're happy ...until he gets into relationships and try to establish boundaries.
Unless there is a legitimate reason with evidence of him being an unfit parent in any way...there isn't much you can do about who he has around the shared child.
Soo..he can't do the things that you're probably doing..but you can?
You
You never said that he was a bad father, and incapable of good judgment when making decisions about the child.
Trust his judgment.
If he has made poor judgments in regards to the women he associates with and allow them to hinder and influence his parent making decisions in a negative harmful way if you have evidence, speak to an advisor or courts.
You two need to change in the ways of co parenting, and strictly parent. What you two are doing isn't working out. There is too much confusion and not enough boundaries placed. It's okay for your child to know that you two aren't getting back together and to show them a healthy separation.
The ringing of each other and discussing general non related to parenting things, should end. Only ring if it strictly about the child. Maybe texting would be more appropriate. Find other methods of commuting to work, decline offers and don't ask him to be a mode of transportation.
The spending a lot of time together probably should end. Every once in awhile a holiday such as Christmas can be spent together, as long as it's a gathering..not an intimate setting. No more weekends spent together. Just meet up in public to exchange the children.
Have the visits without one another.
If you two are still involved sexually, that should stop.
It doesn't make you three less of a family with boundaries in place. .to parent without being in each other's presence.
Your child will still thrive..hopefully happily.
The both of you, if parenting style not corrected and the lines continue to be blurred...will send your child mixed signals, and the confusion and thwarted optimism may lead to depression ..their mental health and well being affected.
Please dismiss the new relationship and person..
If you haven't truly moved on, please learn to do so..perhaps therapy would be beneficial.
Never use your child as a pawn.