That’s tough. Regressions are so hard. Maybe if he’s going in the same spot every time, put a little potty chair there? Get him to use that instead of the floor, and give him praise when he does. Then move it into the bathroom after a day or so, or when you think he’s got the hang of it again. Then transition him back onto the big toilet. I’ve heard with regressions it can be helpful to go through all the training again. They pick it up very quickly because they’ve already been trained. Seems like your bf leaving (good decision, btw) is hard on him. Give him extra hugs and cuddles. They’ll go a long way with his mental health, which correlates to his development. Also, don’t forget to give yourself a pat on the back for kicking out an abuser, going through all that stress, and still being patient with your child. Good for you!! 💪🤗 👏
Get pull-ups asap and maybe if it's accessible to you, a child behavorist/therapist. May need to take back the reins and Take him to the bathroom ever 45-60min till he resettles