Combination problem emergency

I've read through some of the commonly asked questions and there's some great advice but I sort of have an emergency here. It's a combination problem.

We have an older female cat (10+ years) that was our only pet for a long time. Then about 6 months ago we got a female dog. The cat doesn't like the dog but soon things were reasonable other than the cat occasionally swatting the dog a couple times when it wandered too close.

A couple months ago we got suckered into taking in another cat from someone who was moving and couldn't take it with them. It's a male cat that's possibly not quite fully grown. The younger cat gets along great with the dog but the cats don't like each other and things haven't got much better over 2 months between them. I wish I had read some of the suggestions on this site a long time ago about that.

When they end up too close to each other the younger cat always starts hissing. They end up in little quick fights fairly often and I'm pretty sure it's the older cat that mostly attacks but I can't be certain because we usually aren't looking at them when it starts.

So now to the big problem. Over the last month the older cat has started peeing around the house very often in various places. It's making my wife very upset. I thought maybe it was marking it's territory because it was fed up with the new additions but after reading this site it doesn't seem like spraying. I think it's just peeing. One place it's been going is on some curtains that are a couple inches too long with the bottoms on the floor. There's a enough volume that it soaked into the hardwood flors and left a stain.

I took my daughter on a trip last weekend and my wife was so fed up with the situation that she dropped the old cat off at the animal shelter. My daughter and I were outraged that she did this without consulting us. We really want to go get the cat back out of the shelter but I'm going to need a good plan to fix the situation if I'm going to avoid more family strife.

If I had to choose between the two cats I would keep the old cat. It's been with us a long time. I don't know that removing the new cat would stop the peeing though. I can't even say for sure that the peeing is related to the new cat/dog, it just seems to roughly coincide.

I like all 3 pets and just want everyone to get along and not mess up the house.

Any help would be greatly appreciated.

This is the craziest part of the situation and really complicates things. Coming back from weekend trip to find the cat gone really upset my daughter and I. My daughter said at first she didn't want to get her mom any Christmas presents but ended up getting her somethings yesterday. My daughter is not talking to her though. There's been a couple heated arguments over the situation too.

My wife said she thought it would be easier if she did it while we were gone. I haven't quite figured out how she came to that conclusion. It's certainly made things WAY more difficult.

She actually volunteered at that shelter walking dogs for months. She should know that. In anger I did say "that cat is is good as dead" which probably isn't helping to calm down the situation.

I work full time and my wife works maybe 15 hours or so a week. She certainly has found and cleaned up most of the pee since she's home a lot more than I am. She feels like she's the only one dealing with the problem.

I should have been on this site and researching about the problem a lot sooner instead of letting it get to this point. If I get the cat back and it starts peeing around the house again and my wife ends up cleaning up after the cat all the time there's going to be some real problems.

I'm certainly going to have to be more involved and get my daughter more involved.

Everybody here seems to be in agreement that there's a good chance it's medical issue and maybe not a reaction to the new pets. Or perhaps a medical issue caused by the stress of the new pets.

I'm going to suggest that we get the cat back and take it to the vet right away and try some of these other suggestions.