Male cat pooping & marking

We have two cats, a 13-yr-old male and a 12-yr-old female. The male has two frustrating behavioral problems - (1) he poops to show his displeasure if he's not getting enough attention or one of his loving family members has been away; (2) he sprays to mark his territory at front door or in the dining room near the back yard. The former is irritating as we feel he's just being petulant, but easy to clean up as we have all HW floors. The latter is more work to clean up - spray with an enzyme pet odor neutralizer and wipe up with about half a roll of paper towels (

As irritating as 2nd behavior (marking) is, we understand his motivation - marking his territory. We are 99% certain he does it when he detects presence of a neighborhood male cat. He has periods when he doesn't do it for days, then does it every day for a few days. We are wondering of there is some product we could use on our front porch and the boundaries of our back yard to repel roaming male cats without making him uncomfortable in his own yard.

BTW he has no problem using the litter box (we have two); UTI unlikely. The female cat is no trouble whatsoever.

Appreciate any suggestions.

I assume he is neutered right? if not there is nothing at all you can do. If he is, have you tried Feliway? It comes in a plug in and a spray. The plug in is sort of like a Glade plug in but you can't smell it, only the cat can. The spray would be ideal on the exact spots he is spraying on. It is expensive and some people swear by it and others think it doesn't work, but it may be worth a try.