OP, I went back to my DH ex now. He promised everything under the sun, and HE knew what I needed to hear, he played the part to reel me back in, the hoovering tactics, the love bombing, the "I am so sorry" this was so not me kinda thing, over and over again. Till I returned to the family home.
Well, it took him a week till he reverted back to the asshole true self. A week. So, take it from me, it took me 3 further attempts to leave the bastard after that, and ones someone chooses to emotionally, financially, sexually or physically abuse you, because a person always thinks about these actions first prior to acting on them, so its a choice for them in order to control you, its not love, its what comes with you, the benefits of having you, its never about love, abuse is not an accident, not your fault, its a choice.
Why bring a child into that? You may be able to digest it emotionally, but your child will not have a choice in the matter, so act in the best interest of your child, call your mate who is a safeguarding lead and tell her to wobble your head my love as he will choose to blame you, and do far worse things second time round.
The reason you are wanting to go back is because your head is being messed about by your ex. Its terrifying not knowing what the future holds without the "love" from your ex, its the uncertainty of "will I find love again" and the "but I love him so much that makes us think that perhaps your situation will be different.
Now I want you to remember the feeling when you picked up your child and the feeling you had when you left your DH last time, how terrifying it was then, now sit with that feeling, and ask yourself if you are willing to go through all that 100x over again and again, because the two of you have "things left to do in order to be good, your DS has no choice, and I had to go to a womans aid refuge, saw things there, both courage but also defeat where some mums decided to go back, and hearing how social services were all over them, and on one occasion taking a child into their custody because some woman could not safeguard her child. So safeguard your child, that is your duty, its not your duty to raise a man, and believe me if you do go back, you will loose friends, you will get isolated and it will be far worse staying together than the pain of starting over.