Dear LotusLove:
The two of you decided when you moved in with him last time what not to do: “No more games, No name calling, and no ending the relationship unless we really mean it”- but the two of you didn’t decided what to do instead.
When not living together, during the last separation, he may have worked in counseling on some issues and both of you had positive intents, but when living together same old triggers returned and then the same reactions to those triggers. It is similar to this: away from the bakery a person on a diet is doing well, not eating cake, but once back in the bakery, triggered by the sights and the smell of baking cakes, the person eats and eats cake, even if he decides ahead of time to not eat cake.
I suggest the two of you decide of doing something positively different when living together: quality couple therapy if you can afford it would be best. In absence of that, you can maybe get some good literature on communication, a workbook, and the two of you can do the exercises there. Spend some time doing that every day.
anita