Bringing home a pet
Let’s be honest: you won’t be the only one taking care of that pet. There will be times when you’re tired or stuck in traffic and want your partner to walk the dog. You’ll ask him to pick up pet food on his way home from work. Money for vet bills will come out of your joint vacation budget. Pets are a big deal!
So long as that money is just your money, and by investing it, you don’t affect your ability as a couple to keep up a certain lifestyle and cover your expenses, then you don’t necessarily need to consult your partner.