Is this more than just a 'one-off'? If so consider a change of wife.

She accepted her friend's invite and is taking the family with her rather than making thanksgiving with her own family. She is prepared to place that ahead of your being decidedly uncomfortable. 'Get over it' being only a bit better than 'F* you, I have decided' imo.

Possibilities
1) She was aware of your feelings regarding the dog, but went ahead anyway (see para 2) or maybe

2) She wasn't aware of your feelings, despite being your wife and presumably present at the previous incident (see para 2)

3) Her friend means more to her than you do.

Do you and your wife perhaps need more (or better) communications?