It's just occurred to me that every time I suggested a sleepover once we were at my place already, plates always come up with some sort of excuse.

"I'm wearing my lenses today"
"I have to be home early" (lives with parents, stays up all night with me before)
"I have to do something tomorrow"

Is sleeping over something they reserve for boyfriends and if so, is hinting a sleepover therefore a beta signal and something that I should wait for her to initiate herself?

Seems like they might assign more intimacy to it than a man would.