Just count to 10 and be happy with the things that you do like about him/her.Be thankful you still have them around...
I love him so much, don't get me wrong. You know what I do? I reach for his hand in the car and tell him I love him when I get irritated. It's a great diffuser and reminds me that ultimately I do appreciate having him around. It's my annoyances, not his quirks. I definitely breath and don't react - much, haha!
Gawd, I think of Mum missing Dad so much now - she would give anything to have him around playing his music 'too' loud or not making the bed.