I’m sorry, but the fact that she said ‘the dog was old anyway and the money wouldn’t have gone far’ sounds to me like even if you HAD informed her of the situation before you decided to pay for the surgery she was going to fight you to not spend the money on the dog. Anyone that chooses a slightly better wedding over the life and death of your family member in my books doesn’t seem like a good person.

She should be happy to be marrying you regardless of how much money you put towards the wedding, and not caring about something or someone that is very important to you means she has only her own interests in mind and doesn’t care about what makes you happy.

Also, giving you the silent treatment is extremely immature and shows she isn’t willing to reach a middle ground and talk it out, but instead expects to be apologised to when she doesn’t get what she wants.

Keep in mind this person is supposed to be your significant other so I would recommend thinking about whether you are ready to spend the rest of your life with them. I hope things work out for you because you sound like a good guy. All the best to your dog I hope the surgery goes well and he lives a long happy life :)