I found out my girlfriend has been using tinder while studying abroad so I plan on dumping her.
That must've been painful. She should've talked to you about her feelings and the relationship first.
I honestly don't know if studying abroad is something she should still be doing.
It's understandable why you would not want her to study abroad anymore, however you shouldn't try to jeopardize her education because it can have long term negative side effects. The best thing to do would be to talk to her and express your feelings. It's not unreasonable for you to end the relationship in the end.
I'm going to dump her.
It's completely understandable that you feel hurt by her actions and breaking up with her is a reasonable response. So long as you don't jeopardize her education, I think you should be confident in your choice, as you deserve a partner you can trust.