@25 years old that's quite a bit to give up for love.
Try making a list of the pros/cons of staying and the same for leaving and see what you come up with.
In my opinion, this is one of those very few posts where the OP has full information, and a clear idea of what the different consequences are, and has to make a decision.
This is up to you. Most people who post here really are unaware of life consequences, and facts, but you know them.
And now, you need to weight this and make your decision.
First off, is there any chance of the ex ever moving to a bigger city? He might feel as hamstrung in the small town as you do. You may as well rule out the possibilities first that would mean you still don't have to make a choice.
But if you do have to make a choice, I noticed that in your explanation you said "I could see myself spending my life with her (she is beautiful, intelligent, we have sex about 10 times a week!)," but you didn't begin your story with "I love my girlfriend and can't see life without her," or "She makes me so happy I can't imagine ever doing anything but being by her side." You sound like you could readily enough see life without her, and that it has some advantages over life with her.
If you have the potential to be one of the best of the best at what you do, and if this is important (to you and potentially to the world that you would impact if you got that good), and you don't feel incomplete without this woman as your wife, then it seems like if you stop at age 25 and park yourself somewhere that it won't happen, you are potentially always going to regret your lost chances. It's bad to get to 50 and feel like you turned your back on an exciting and desired future. Your girlfriend sounds wonderful, but other women in the world are wonderful too, and you might meet someone as portable as you are. I wouldn't say this to you at 45, but at 25 you do still have the chance to put it all together if you are ambitious enough and work really long hours and learn your craft and devote yourself to it. Have you had offers that you have turned down? One last thing to assess is how hot you really are. If you seriously think you have the potential, fine. If you are just kidding yourself, think it over before walking away from someone great.
Hi there. Wow, tough dilemma for sure. I feel for you as this is indeed difficult. I'm going to be straight with you. This comes from an older woman in my 40's that was a career person that married an ambitious, successful man. I wouldn't trade what I did to get ahead early on for anything. Nor would my husband. We moved to places for jobs, we put a lot of effort on getting ahead, we progressed with our careers. My husband is now our financial supporter and I stay home with the kids. He's very successful because he set himself up to be that way when he was younger right out of college. But these are the choices we made to make us happy.
You have to make your own choices here that will lead to your happiness.
This woman has more than your average to consider. Many relationships work with ex's 4 hours away and sharing of custody. Is it best for a child? Probably not--- it's hard on them. But couples make it work. But if you are saying this is not an option---- you are going to have to follow what you feel is best for YOURSELF.
I've loved many in my lifetime and met my husband in my 30's. This isn't your only chance at love if you find yourself pulled by career. And then again, in the end, it's our loved ones that matter most. So, you are just going to have to think about this really hard and do your pros and cons list.
There is beauty in whichever way you go so pick what is best for you. peace and luck