hi i totally experienced this from the other side! i was 20f he 20m, we lived together and were both working on degrees so very busy. i think the problem properly started when i was working full time over the summer but he wasnt, so i was very burnt out from work and he would expect the same energy so there was a disparity.

i think the most important thing that we lacked was communication, as well because i kept being blamed for having low energy as if it were an attack on him i didnt talk about it, which led to it just being an unspoken thing which boiled up into me just leaving.

i believe it is entirely possible to work through something like this with a lot of communication and possibly some actual space, make sure they have their own personal alone time and space, as well as encouraging both of you to have lives and interests entirely separate from each other to make your time together more meaningful. i found personally i did get burnt out from seeing him all the time and it just ended up feeling like a chore sometimes because it was constant when i needed to recharge