I do think you should make decisions in your own best interests and those of the kids too. I don't think you should sacrifice your own wellbeing for the good of everyone else though. It is pretty unusual to have a sitch like yours where the W comes and goes and retains the family home as a partial residence and still gets to be 'mum' part time in the home environment.
And I do think OM moving in is a bit of a game changer. Yes, the idea of going out on Friday nights may be a good one. Maybe treat her more as a 'sitter' and make that 'your' time - finding a regular Friday night GAL activity for yourself. You know I would love to see you GALing a little more - maybe a regular quiz night or bowls league or bikes meet up - whatever would float your boat.
You could say to her. Hey we'll need to review things at some point. You're welcome to stay in this way in the short term. But let's face it, you're not going to want to bump into my date on a Saturday morning are you?? (I'm kind of joking....but you know what I mean??)
So, why not shelve the letter for now and make this weekend all about planning your new Fri pm GAL activity?
Xx
T 13 M 7 Me 48 H 46 SS 15 BD 7.14 PA D final 5.16 (H filed)
We receive & we lose, and must try to achieve gratitude & embrace with whole hearts whatever of life that remains after the losses - Dubus