DH suffers from insomnia. I have a baby who wakes frequently and won't settle without a BF. I usually end up cosleeping. With a small age gap I haven't actually had a good nights sleep in well over 2 years.
Whilst I know it will pass, I find myself irrationally annoyed when I say that I'm exhausted and he says "I know how it feels"......he sleeps in a separate room most of the time so has nothing waking him!