If I were you I would quit wondering about OW and just believe she is there and they are having an A...all the signs are there and most likely he is lying because he doesn't want to hurt you...
Believe me if he KNEW he wanted a D he would have filed...money doesn't stop anyone from filing...if you don't have the money you can get a financial waiver and pay nothing...I know...I did that....
He hasn't filed because he isn't sure that is what he wants...he looks at you like he does because he is unhappy inside and probably hates what he is doing...but he is driven...he has to find what he thinks he is looking for...
My H admittedly didn't love me...couldn't show me love...didn't want to mislead me into thinking he loved me...but in time he realized that his "family" needed him...he was a broken man by then and really he needed us...I didn't turn my back on him even though he couldn't tell me he had made the biggest mistake in his life...he could only tell me how sorry he was when he was drunk...eventually he had to admit that he was now an alcoholic...probably had been for a long time but being a family man kept it in check...now he was out of control...it was hard...I stopped covering for him and just called 9-1-1 to have him taken to the hospital...he knew I loved him...he "wanted" love me...things were rough for a long time but I kept doing what I could to keep me focused...to be patient...to allow time...it was over a year after he returned that he took my face in his hands after reading a few Bible texts on love...and he said that he could now say "I love you" and mean it...I cried of course...but this time tears of joy and relief...I knew I had won him back....
I don't think your finding yourself was exluding H...he went to work...you created a work you liked at home...it is more just a matter of timing for him...MLC...it is real...it is confusing...but it isn't the end...time is on your side...the longer he goes without filing the more likely he isn't going to do it...and even if he does...it isn't the end...
You do have positives...he invited you to SIL...and to BIL for a BBQ...my H wouldn't have done that...so just remember...no matter how he looks at you...now matter what he says or does...no matter if their is the OW and an A going on...this doesn't mean the end...give it time...
And...don't ever expect the light bulb moment of "OH MY GOD...what did I do to you and the kids? I am so sorry!"...most likley his pride (most men have an overload) he will just want to come back quietly and pretend that all if fine...this is where it gets hard...you have to let things go...until the foundation is rebuilt...then time will allow for you to talk about and resolve the issues...but that is yet to come...for now...keep feeding the birds...planting the flowers...watering the yard...enjoying your girls...and living life...one that he can come back to...but one that allows you to be happy either way...