I [21 F] feel guilty about starting arguments with my boyfriend [26 M]

I'm on Reddit pretty often, so if you recognize me, hello! Back at it again with the relationship problems (ha. ha.)

To sum it up, I have a lot of self esteem, insecurity, and jealousy issues. But, I've been working on them and actually improving. My boyfriend and I have had tremendous ups and downs, but for the past few weeks (with maybe one or two little outbursts) we've been great. We spend quality time together, plan dates together, are affectionate, and display our love to one another often. It's been great.

These past few days however, I haven't been keeping my emotions in tact. One thing about our relationship is that we have sex typically 1-2 times a week. He works the night shift (12 am - 9 am) 5x a week, sometimes 6, and is completely overworked and exhausted. Therefore, we don't have sex that often. Which is fine to me! It's been this way for awhile, and although at first it was hard to understand (I thought our lack of sense was because I was unattractive, not fun, etc.), we got through it.

However, like I said, sometimes I have my off days. Today was one of them. I slipped in a quick question, whining basically, asking if he didn't want to have sex with me because I've gained weight (which I have). He immediately blew up saying, "You KNOW I'm tired from work. Why are you trying to pick fights? I'm so tired of this." He stormed out of the room and went to the other room to sleep because he has work later tonight.

I feel bad. I honestly feel terrible because I knew this was just a comment that wasn't a true concern and I was just being needy. I knew that our lack of sex was just due to his work, but I let that tiny voice of insecurity in my head take over for a second.

I know some of you might think he should be more understanding, but I really do understand his point of view. It gets frustrating when I say/ask things like that when I KNOW the true reason behind them. It was unnecessary and adding to the stress he already has for no reason.

I just feel really guilty because I know how much stress he is under already, and us fighting doesn't help whatsoever.

Do you guys have any advice for how I can control myself better and also just how to make things right with him? I know that after some space we may be okay again, but I still don't think its right. I hate straining our relationship with problems that don't exist and I truly don't want to lose him.

PS: I know people are going to suggest therapy, but any other forms of advice are greatly preferred/appreciated.

Thanks in advance, Reddit.

TLDR; I pick fights with my boyfriend and feel really bad about it. Does anyone have any advice on how to improve myself and how I treat my SO?