Can you at least join them at dinner even if you get there late? Or have cake later at home?

It doesn't seem right for you to miss dinner/celebrations altogether.

I know what you mean about doldrums of DBing but it does sound as if your W sees that you (as a couple) are different now from before. I wouldn't discount that comment of hers.

Good luck!

Me: 51
H: 52
T: 23 yrs
M: 19 yrs
S18, D16, S14 (special needs)
PA: 2003/2004
Piecing: 2004 on
Suspect H had EA: 8/2012-12/2012