I agree you definitely need to make a list and give it to the therapist ahead of time. Put LYING/TRUST as the #1 issue. As much as other issues are a problem, it all comes back to trust.
I guarantee your therapist is used to having people try to play their games with them, and is going to not take everything either one of you says as absolute truth. It will take time, though for the therapist to get a feel for each of your personalities and listen to you talk enough to start to grasp some of the underlying issues. Not to mention that each person's "truth" is coming from their own perspectives and through their own viewpoints, with all of the crap that comes with that, and that's part of their job, to help figure out what is going on with all of that.
Many people think that if they are "playing" the therapist and they don't call them on it straight up (or on the first visit), that they're somehow fooling them. But any good therapist is #1 going to take time to get to know everyone, and #2 not call someone a liar, even if they think they're not getting the truth. They will, however, ask questions and get people thinking for themselves.
Hopefully a third party will be able to at least get the communication moving about these subjects without all of the recriminations, accusations and the gaslighting. He's definitely trying to make you second guess yourself to take the heat off himself-- and it's mostly likely worked well all of these years so he's probably confused as to why it's not working anymore.