This book (君愛) is part of a pair, the other being 僕が愛したすべての君へ (僕愛). Both could probably be enjoyed individually and they can probably be enjoyed in either order as well. That’s because they both reference and (loosely) spoil events from the other, and you’re likely to have some “ah ha” moments with whichever one you read second, but in neither case are the events of one a requirement to understand or enjoy the other.
That said, there is an argument to be made that 君愛 should be read first and 僕愛 should be read second. There are some story reasons for that (which I won't spoil), but primarily it's about tone. 君愛 has a very subdued (arguably sad) tone, while 僕愛 has a much happier tone. I read 僕愛 first and really enjoyed it, and while I enjoyed 君愛 as well, its sadder tone left a bad taste in my mouth. I feel like if I had read 僕愛 second, I would have had a better experience overall. So with that, I recommend either skipping 君愛 entirely, or if you're willing to commit to reading both, read 君愛 first, knowing that you're getting the better of the two stories second with 僕愛.
This book (君愛) is part of a pair, the other being 僕が愛したすべての君へ (僕愛). Both could probably be enjoyed individually and they can probably be enjoyed in either order as well. That’s because they both reference and (loosely) spoil events from the other, and you’re likely to have some “ah ha” moments with whichever one you read second, but in neither case are the events of one a requirement to understand or enjoy the other.
That said, there is an argument to be made that 君愛 should be read first and 僕愛 should be read second. There are some story reasons for that (which I won't spoil), but primarily it's about tone. 君愛 has a very subdued (arguably sad) tone, while 僕愛 has a much happier tone. I read 僕愛 first and really enjoyed it, and while I enjoyed 君愛 as well, its sadder tone left a bad taste in my mouth. I feel like if I had read 僕愛 second, I would have had a better experience overall. So with that, I recommend either skipping 君愛 entirely, or if you're willing to commit to reading both, read 君愛 first, knowing that you're getting the better of the two stories second with 僕愛.