Is it healthy to be annoyed with your partner?

I love my fiance but I get so annoyed by the littlest things sometimes with him. I love being with him and spending time with him.. but Ive realized I definitely need my alone time too. Specifically I feel bad because he is military and has been on a boat for the last week. I've barely talked to him for more than a couple minutes on the phone without becoming annoyed... even after having hours of alone time after work. Is this normal? I feel like it shouldn't be this way, and I don't WANT to be annoyed by him. But I just instantly started feeling antsy and annoyed when he called /: even when we didnt call for several days. I feel like a bad partner