The only prep I can think of is if one or the other of us really needs to take a piss first. Otherwise, you go with the moment.
God, that would kill our frequency. How does one get anything else done, if sex takes an hour+ every time? No. As long as we aren’t* too* disgusting, we’re good to go.
Maybe I’m unusual, but I actually think sex is best when we’re not right out of the shower. If we showered that morning, then sex that evening is perfect in my mind. If either of us has to use the bathroom, then we’ll head off to do that before things proceed, but we don’t do any real prep.
Well, a couple dabs of lube, give the downloads a couple minutes to finish, and I’m ready to roll.
We shower before bed every night so we’re good to go whenever.
Unfortunately, with two small kids that isn’t nearly as frequently as when we were trying to make said children.
If I’m particularly gross, I’ll jump in the shower. Regular day dirtiness? No problem.
I can’t imagine why I’d need to shave.
Holy moly, what is the OP’s spouse doing in that shower? I couldn’t make a shower and shave last 45 minutes even if you paid me to do it!
Generally, I’m with the “unless totally gross just get down to it” camp. Even then, basic clean up shouldn’t take more than 10 minutes unless maybe you have remove roofing tar or something.
Come to think of it, we usually clean up after sex, not so much before.
Take a pill, wait half an hour or so for it to kick in…
Oh, he cleans up afterwards, too (with another mini-shower).
We’ll shower for sex only if we’re really gross, but we tend to try and get those showers out of the way earlier in the evening, not right before sexy time.
I sometimes prepare for sex by masturbating. Clearing that first, sometimes premature, ejaculation out beforehand makes the sex much more satisfying and enjoyable. For both of us. 
Our preparation typically involves my wife reaching over to put her hand inside my shorts while we’re sitting on the couch watching TV. If we have time in the morning, it involves me rolling over to spoon her and nestling myself between her cheeks. But during morning sex, no kissing since we haven’t brushed yet.
A 45 minute shower and shave? The only times I’ve taken a 45 minute shower were when we’re both in there and it’s part showering, part fucking.
Can’t you just move the dishes out of the way?
The Viagra takes about an hour to kick in so we have to do something. Showers and walking the dogs works for us.
Maybe this is why the OP’s husband is stalling.
There’s more? (Sigh… For a fair many of us, that’s all we got!) I prepare by opening the file-folder of really good porn…
Makes me think of Gilbert Gottfried’s routine where he talks about being in a hotel room with a prostitute. She goes to the bathroom to change, and when she comes out, he’s masturbating furiously. She asks him what the hell he’s doing, and he says “For $300, you think I’m gonna give you the easy one?” 
We basically just say “Let’s have sex,” get somewhere alone, and go.
“Sex,” to my partner and me, can mean just about anything, and usually needs no preparation, except to pee if one needs to. We’re used to each other’s smell, and that adds to the experience. So all we have to do is cuddle for a while, wherever that may lead, or go up to the attic dungeon, and see whether something inspires us.
Ok seriously I don’t do anything to prepare, but my wife if it isn’t spontaneous sex goes and takes a shower and uh washes downstairs with soap. This is horrible both for oral sex taste wise, and makes natural lubrication harder, I wish she wouldn’t do it but she wants to.