Well I don't think moving back into the house unannounced while she is gone is the answer. Is that really how you want to start putting things back together by doing something unilaterally and without any warning to her.
I suggest you instead explore the option of beginning some MC together to start working through the issues that have cause the M to falter and what it will take to rebuild it. From those sessions you can jointly map out a path to your moving back in together. Good luck.
