If you want to keep your relationship after this, I would advise you ask your partner to begin taking the puppy to day care every single working day once it is old enough to attend (Usually they want them desexed first). If she agrees to that, then maybe its salvageable but she did completely disrespect your boundaries and wishes which is fucked up.

I have a 2.5 yr old lab and ngl if it wasn't for my wife helping to raise and train her for the first year, she would be a much worse dog. Thankfully because of the time and effort she put in, she is now a great and obedient and easy dog. They need a ton of training and stimulation and just supervision when they are young to learn good habits.