OK, well it does sound positive, but it is very common for a WAS to promise to end an affair and then either not do it or revert back to it a few days or weeks later. If she's serious then there needs to be some accountability, like full access to her phone and email so you can verify she really did end it. That may sound scary to you, you may be thinking "she'll never agree to that". If that's true then she's not serious about the M and this effort has failed before it has started.
You mentioned "we have stopped seeing the MC because it was usually during these sessions that things turned from positive to negative". It sounds like you have a poor MC. Finding a good MC can be a really lengthy process. You might consider a DB coach instead, they offer couples phone counseling in addition to individual counseling. And they are totally pro-marriage all the way unlike most MC's out there. Or depending on your funds you can always fly there and get counseling from MWD herself. I would totally do that if W were willing (she's not).
Also check into Retrouvaille, it's an amazing program, IF your W really does want to work on things.
