One of the things about boundaries is that its not about what you want them to do its about what you will do or not do (its all about you)
so on the financials it is NOT 'I want you to pay more'
it is more 'Given our current circumstances I will now only be paying 50% of the household bills. Should our circumstances change then I am happy to review this arrangement'
ok the phrasing isnt great but hopefully you get the idea
As for valentines day, not going back so she cant go out is punishing behaviour (probably not good). Besides it will be easy for her to sort an alternative sitter if it comes to it so it probably wouldnt have that affect anyway.
Not going back because you dont want to or have other plans is another thing altogether. Have you thought about taking the boys away for a weekend (maybe all do a snowboard course at MK or Tamworth)?
Both mid 30s, 2 young kids BD 7sep14 XW moved on long ago, now living with OM1 D paperwork in progress
