Boyfriend is always too tired for sex

I've been with my boyfriend for 7 months and we've never been rampant as such. I liked that about him as my previous relationships have felt way too much about sex so it is refreshing to meet a guy who doesn't make that his priority.

However... it's got to the point where we can go 3 weeks with NO sex and maybe a week or 2 with no sexual encounters at all (sometimes we just go down on each other instead).

I have quite a high sex drive and he's really good in bed so I'm getting so frustrated. He works long days is quite a stressful job so I get that he's tired but it's upsetting me that he is so rarely in the mood.

He's also only "jumped me" ONCE in 7 months. It's starting to make me feel super frustrated and like he doesn't find me physically attractive.

Also he's defensive when I bring it up and says "It's not even been that long." And "I'm tired, I work a lot." 🙄🙄🙄