I'm sorry to say -- both for you and for me -- that I think by the time a marriage gets to a point where a spouse has chosen to separate in-house or into another house, severe damage has already been done to the marriage, and that spouse has already taken a huge mental and emotional leap ... and they are highly unlikely to take the leap back into the marriage.
Which is why many tell you that you have to consider the old marriage dead, and try to be a new, attractive person that the spouse would fall into love with -- but that also seems to me a highly unlikely event.
Sorry, for both of us....
Me: 50, MLC/WW 45 Young kids Nov 2015: BD1 Apr 2016: BD2 Jan 2017: W filed Feb 2017: D final