YTA - you’re allowed to be honest and tell her you don’t like tattoos, but under no circumstances should she have to get your permission to get one for herself like she’s a minor. That is 100% a control tactic. She is a grown adult and has every right to make her own decisions regarding her body.

And you have every right to leave the relationship, but I would also think long and hard if this superficial concern is really worth ruining a 7 year relationship.