My SO (M, 25) doesn’t want to get married ever, I (F, 25) do. Should I break up with him now or wait till we can meet up?

I’d say marriage might be something you could eventually find a compromise on but not kids, if you want kids and he doesn’t there’s no room for leeway there. I think he’s telling you now because he wants you to have time to think it over by yourself. So atm he’s probably half expecting a breakup and is primed to deal with it. If you put it off until you see him again a) you’re going to have a miserable, uncomfortable, shitty 2 weeks of either lying or just really awkward convos and b) it’ll get his hopes up that you don’t want to break up and will be crueler when you say you do.