Too tired for sex

I'm 27 years old and just can't get myself to stay awake long enough on weeknights to have sex. I work long days (9:30-7ish), but I feel like I should be young enough to still have energy when I come home. My partner is starting to get frustrated because I keep falling asleep before she comes to bed. Yes, I'm in a relationship with a woman so I can't just lie there...sometimes I wish I was straight just for that reason 😂