NicoleR, Maika tried something like you are suggesting above (back in September 2017 I believe...called it an experiment) and was told no, that the separation was permanent. Since then, she hasn't showed much, if any, movement toward R or that she might be regretting her decision or having second thoughts, so not sure why he would set himself up for that kind of disappointment again (or give her the satisfaction of knowing that he is still attached and wanting her back). Plus, it sets him back if she feels the same way as at BD, or so says the advice on here.
Maika, I do recall however that before Christmas you were gonna try extending yourself just a little, maybe try swallowing your pride (and anger) in certain situations to see if things might thaw somewhat and allow her to see the changes you've made by doing the odd family activity together...not pursuing but just accepting an invitation here and there or suggesting she join you and the kids in an activity.
Did that not work? Or did something happen recently? I get the sense something must have happened (OM suspicions?) because you seem to have got to the end of the rope rather suddenly. Or perhaps your patience has just run out?