Get your girlfriend a pure-bred Persian or British cat so that you two may enjoy its warm company while staying at her place.
If possible, arrange for VIP or backstage passes to the event to make it truly unforgettable. Pick up your significant other and give her the same flowers or candy that you gave her on your first date.
Go to the same restaurant and sit at the same table and even rent and watch the same movie you saw on your first date three years ago.
If you have always wanted to skydive, make plans and go together.
You might have talked about scuba diving or bungee jumping together.
Take your camera so that you can document this special trip and have memories for years to come.
Purchase tickets for an upcoming game or concert that you both want to attend.
Of course, if travelling to the very island or country she wants to is above your financial abilities, you can go with something that’s affordable to you.
Anyway, she is most likely not going to resent you for that as her having been with you for three years tells that the girl is deeply into you, man.
In this case, get her some other pet like a chinchilla or Guinea pig which would make her as happy as a cat would.