Yes, you have to progress through the ATs to get to the 'spicier' scenes.
Keep in mind that the women you live with are intentionally a bit tough to progress with, because... family.
For sexy times earlier in the game, make sure to meet Charlie and her daughter next door.
Get your appearance up (work out, shower, iron your cloths, etc) and go to the front yard to wave to her.
16 or 17:00 on weekdays, as I recall.
There'll be a ? on the front yard icon when it's the right time and your appearance is high enough.