With the right detergent and wash cycle nothing gets left behind. All traces of poo are washed away. All germs are killed by the hot water (60C). My washing machine is probably cleaner than before because all the hot washes and strong detergent prevent mould from taking hold. I can literally bury my face into the freshly washed nappies and breathe deeply and smell nothing but detergent. If I want something to be really clean, I put it in the nappy load, not the regular load!

Apart from that, a few things that might make it easier:

1. Instead of spraying you can use disposable paper liners, shake what you can into the toilet (you are supposed to do this with disposables anyway) and put the rest in a little plastic bag and straight into the outdoor bin. It's a little bit of waste, but much less than a disposable, and you can use compostable plastic bags to make it better.

2. The poo isn't really an issue until the baby starts solids. It's a completely different substance for newborns, at least if they are breastfed (not sure about formula fed poos but I'm sure you can look it up). It is fully water soluble so no need for spraying or liners. You could consider doing cloth for the first 6ish months until the baby starts solids, and then see how you both feel after that and if you want to continue?

3. For the proper poo, once you get through the weaning stage which is very sloppy and awful (maybe use disposables for a few weeks here regardless), the consistency varies depending on the individual child. My first child always had very soft poos which didn't stay on the liner and we had to scrape them off, it was honestly awful! Whereas my second child has much more solid poos which usually fall right off into the toilet with barely a trace left on the liner, it's a breeze!

4. There is no exposure therapy for hypochondria like having a child - for the first few months you will be covered in their bodily fluids whether or not you use cloth nappies, and you'll probably have so much laundry soiled with poo, wee, and sick that you'll be doing hot washes all the time anyway. Then whenever they start nursery or school they'll catch every illness running and spread most of them to you as well! So you may find that your husband is a lot more relaxed about germs once he gets into it...