What should I do when she did something she doesn't want me to do?

So me and my wife of 4 years (we got married out of highschool when I went in for my service career). I use to have a lot of tattoos and piercings I've grow out of them and she told me how she didn't want me to get anymore. I Agreed with her how it was silly I was spending money on stuff that had no real value to me. I asked her If I stopped if she would stop and she agreed. But she came home yesterday and she got a new spine tattoo and It was crazy expensive (around $1000) and doesn't look the best. Now I dont know what to do cause she's gone back on her word before and Im getting tired of it. I had a talk with her about it and she got very defensive saying its not like she has a lot but I dont get why she would go back on her word like this.

What should I do when she did something she doesn't want me to do?
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