Still gaslighting what shall I do?

I’ve been out a few years, got teen kids one with special needs.
I never told ex he was abusive and we still live nearby. It was mainly emotional. Teens didn’t see him through choice for while but now in contact through choice. Teen with special needs has a lot of professionals involved with them. Part of support is therapy as a family, and I’m still helping that teen navigate relationship with Dad (typically professionals said nothing or vocalised better for kids to see both parents).
Now im pretty sure he is gaslighting me, saying things to me in conversation once and never again then when I bring it up he says ‘yeah we discussed and decided x,y,z and I told you that at the time.’ Whereas my recollection is it was loosely x,y or z and he would confirm but he never did so it’s somehow my fault I didn’t know.
he’s said something recently in family therapy about weighing up his options (I’ve paraphrased!)  with regards to seeing teens as he doesn’t think it’s going well. I panicked as it sounded like cutting contact. A week later I mentioned it and explicitly asked about it and he shut the conversation down saying it was not what he meant.

im wondering whether to speak to therapist about it?? I’m worried he’s not changed at all and is just slipping back to he’s right and we’re all wrong. I’m worried about the effects on the teens. I’m worried having him in our lives makes us all on edge. Eldest says she likes seeing him on her terms and calls him out and will come home early if she wants to, but I’m still worried.