When we got together my kids were 1, 3 and 5 and hubby's were 6, 7, and 13 and I'll tell you it was like this
AAAAAAAAAAAAAAAAAAAAAAAAAHHHHHHHHHHHHHHHHHHHHHHH

I finally had it with the these are mine and those are yours BS so I left and told him when he changed it to "We are a family" I'd come home, it took a few days!!!
I feel your pain! and big (((hugs))) to you!
Mommy