If there are financial problems can you not both have showers?
This has been expressed by several PP.
Has it occurred to you for one second that not everyone has a shower?
I would love a shower, mainly because getting in and out of the bath every day bruises my knees as it's got nasty lumpy moulded nobbles on it. I rent, so even if I had the very large amount of money required for the unit and much dearer installation, I don't think the landlord would be too pleased and they certainly would not install a shower.
I think some people may do well to remember that other people's lives may be poorer than their own.
As for sharing bath water, yes my DH does get in after me. We only have electric and one bath a quarter full costs 80 pence a time to heat.
I bathe every day, wash my arse after a shit and don't roll around in the street. I am not covered in shit, piss, sweat, blood, spunk nor does my skin slough off en masse upon contact with bath water. My bath water is the same colour when I get out as it was when I got in.
Saying that, I wouldn't follow DH into the bath because he does dirty the water as oil, grease and metal dust hitch a ride home from his work.