I've been with my DP for over 3 years and we live together.
There is a real issue between us, and it's getting worse.
DP stays up much later than me - I usually go to bed at around 11 or half past during the week and get up at 6 for work. He doesn't come to bed until at least 3am most nights, and usually falls asleep on the sofa way before then.
I'm getting really fed up at going to bed on my own every night. I could understand it if I went to bed early all the time, but I don't.
One of the reasons he says he does it, is that he wants to make the most of his evening as we both spend all day at work, I totally get that.
But it's lonely when it happens all the time. On the odd occasion that he comes to bed at the same time as me, I've woken a couple of hours later and he's gone again 
I find it upsetting. I know that sounds daft. I don't want to tell him what time to go to bed, he's a grown man - but I also don't understand why he feels the need to stay up so late every night.
He disturbs me when he comes to bed - I'm not a particularly light sleeper, but he faffs around getting into bed and putting his phone on charge and wakes me almost every night.
I'm aware that this sounds like a really trivial complaint, I know. But it's affecting my relationship more than it should and I can't see a way forward.
Does anyone have this problem? What do you do? Just let them get on with it? Does it damage your relationship?