It's the skirt. You need a plain black skirt (of any length, tho idk if the Maxi Skirt works) from the basic clothing store (Mr. Gable's)
Or pants as he tells you, but obvs if you're aiming to wear a skirt, that's the one.
I'm having that same problem. I got my character a girlfriend and then started working on getting a boyfriend, all his stats were up and I was going on a date every night for weeks but the prompt never showed up. Finally, I broke up with the girlfriend and next date? He finally asks me to be his partner.
And while all this is happening, I've been stuck in a loop with the Best Friend, I rarely get the option to even talk about sex (despite my character's stats) and when I finally do it's never the scene that resolves their storyline. I guess I'll try breaking up with my character's boyfriend to see if that works, but it's really frustrating if choosing to be poly locks me out of actually being poly.
I found this game a while ago, but kept forgetting to comment. It's all I ever wanted 馃檹 In earlier routes, I could see room for improvement in the writing (as well as typos and grammar mistakes) but it seems like your writings improving as you go! That's good! And I LOVE to see content made just for Bottoms, and with a bunch of hot Tops all over the place 馃槏 I can't pick a favorite lolol. Great game!