Piecing was harder for me than BD and S were. It absolutely cannot happen with another partner that's not pulling their weight equally
My H and I have been through some trying times during piecing and I backed off like you did. Went out and GAL and reminded him (and myself too) that I would be just fine without him.
We made the mistake of moving too quickly without really fixing what got us to BD in the first place so if there's any advice I can give its to look at what happened prior to BD. Nobody made her have OM but I'm sure there are things you both know can be done better. We know you are working on yourself, but is she? If she's not then she's not deserving of your love and attention. Until you can both decide you are both going to do whatever it takes to make this M work you should back off and GAL.