Recently I realized that I think I pick relationships based on how easy it will be for me to leave.
That's a good realization to have. Why do you think you choose those kinds of relationships?
I just don't want to be stuck in a relationship without some way to leave.
I get that you may want an easy escape route, but being in a relationship means lots of commitment. You are devaluing your relationship by having this escape, and you're telling the other party that they already might not be worth your time.
It's the 21st century so I can make my own choices about my relationships.
Of course you can make your own choices, but I don't think you should be getting into relationships with the goal of getting out of them easily. It really isn't fair to the person you're in the relationship with.