High school sweetheart + long term relationship

Please disregard my username 💀 so I am mostly looking for advice from anyone in their mid-20s who are dating or married to their high school sweetheart, but not necessarily. just any long-term relationship in general would be fine. I (24F) have been with my bf (25M) since we were in high school. I was a freshman and he was a junior. The first two years of our relationship we had lots of sex, but then it just suddenly stopped and it turned into sex every 3-6 weeks. During Covid was the worst because I was an “essential” worker so I had to keep working, but he was able to get the unemployment checks and stay home and play video games all day and during that time he just barely even wanted to hang out and we barely had sex. And I have always told him that I have a pretty high sex drive. I would really enjoy having sex at least once a week but after 2 weeks, I’m already… in the mood, ya know? He always gets really sad and feels guilty and ashamed whenever I bring this up and he always told me the same thing that he’ll work on his sex drive and that he will try to do it more often but nothing ever really changes and I’ll say about 50% of the time it’s me initiating the sex. My main point is, I’m wondering if it’s normal for high school sweethearts who are in a long-term relationship in their 20s to be having sex only once a month? sometimes even less than that. I’m not sure what else to include in this post but I will say that he definitely is not cheating on me. We used to work together up until maybe a few months ago and we are basically together 24/7 and so he’s not cheating and I have caught him maybe three times in our whole relationship with porn on his phone, but he really can’t be watching that more than maybe once a week because he always falls asleep before me and then we’re just basically together almost 24/7. If you have any questions, please feel free to ask me, I’m an open book but any advice would be appreciated. 🙏🏻🩷