cat peeing/spraying

I have two 5 year old male, neutered cats. One of them has either been spraying, or peeing around the house. We are not sure which one, but we have a pretty good idea because he has always been extremely jealous and needy lol. On the weekend I noticed that he had sprayed/peed in the dirty laundry basket. It was full of towels and had some of my husbands hoodies in it. My husband said today that he can smell it and is wondering if he also peed/sprayed in his shoe! (still waiting for confirmation on this haha) I do not believe it is a litterbox issue, in the past if they were unhappy with the litterbox they have gone on the floor right infront of it. I believe this has to do with a cat outdoors. We moved into our house at the end of January, and since mid May or so, a neighbourhood cat has been coming around and we were giving her food and petting her a little. I have stopped, but my husband still feeds her every night and sometimes goes out and plays with her for a couple of minutes. We feel bad because she is ALWAYS there. She sleeps on our back porch and is always at the window. I know a big part of this is our fault because we give her food, but we are a sucker for animals. Now it appears we are paying the price because my male cat howls at her and stares at her through the window all night. She has been around for awhile, but I am just noticing the spraying/peeing now. From using google, I am reading that if cats see an outdoor cat they usually spray the wall or window. So far this is not the case as the laundry was down in the basement and the shoe if peed in, was by the front door. BUT everything that has been “marked†so far has been my husbands which makes me think this is a territory issue. Any advice? Obviously the first would be to stop interacting with the cat outside but anything aside from that?