Hi gymlozza, my first thought when I was reading your post that it is so very important for you to keep the lines of communication
open all the time with your partner, that is #l.
You can still have spontaneous sex, it might be a little one sided at first but I would suggest that if your partner is ready for sex, than satisfy them first, then you can go have your shower and then carry on after your shower.
You might be feeling a little bit anxious when your partner is raring to go and you are not, so this way you won't feel like you are having to make them wait while you get yourself ready.
I hope you don't mind that I am being so frank, it is just that I thought there wasn't any other way of saying this to you, if you are offended by what I have said, I apologize.
If you are not, I hope what I have said might help you, anyway good luck with things and keep the lines of communication with your partner open.