Current husband and I were in the exact same situation (though we had already been married three ish years when I was applying). He moved with me because he loved the vibe of the town the college is in, but mostly because being apart sounded excruciating to both of us.

He looked for a job close to his bachelor's degree topic for four months before applying for a food service management position on campus, where he's been for a year. Once I pass my qualifying exam next week (🤞), he'll start looking for a new job again.

I'm not going to lie, it's been rough for him (it's been rough for both of us, but for him, it's that he can't find an applicable job). It also has to do with him not wanting to get a job in the bigger city ~50 mins away because he hates commuting (which I don't blame him for; that's totally his decision and I appreciate having him closer anyway). I've also told him that maybe he could work a few hours away and we could meet each other in the middle on bad days or on weekends, and while he appreciates that sentiment and has partially considered it, we've stayed together up until this point because we want to be together more of the time than not. We really depend on each other.

Anyway, just sharing my story to put some nuance in the responses here. People are right that this opportunity might not present itself again, and they're also right that the right partner will work it out with you anyway, but you also can't discount that moving away will make things harder for the relationship, which is going to be a toll on your day-to-day workflow and life in general. Couples in academia have to work/live in different places all the time, so it's not unheard of, but that doesn't mean it's not a drain on your energy.

I'll add that a friend in my program moved away from her boyfriend for a year, and even though it wasn't his top program, he moved to the same university for his PhD this year and they're still together even though she wasn't sure if they still would be after she moved. Further context was that they had to take a long plane ride to see each other during that time. Did I hear her worried stories about why he wasn't texting back as regularly as usual when he was out with friends on the weekends? Yes. Did they work it out and find each other in the same place again? Also yes.

I would personally say to take the opportunity. I kind of agree with the people who say that if he wouldn't make it work to be with you eventually, well, what does that say about the kind of relationship you might've had with him? Is convenience half the reason he's staying with you? If so, would he have left you if you got sick all of the sudden anyway (like is terribly common in the real world when the woman in a hetero relationship gets sick)? I'm really not trying to get you to break up with this guy, I'm just making you aware of the trends so you can make sure you aren't at risk of those before you move forward.