We have two neutered male cats. One is a homebody, who occasionally will go over the garden fence; the other goes out exploring during the day and we think has quite a large territory. He does have a curfew at night though, 9pm in summer and 7pm in winter (to coincide with food times...) He may like to roam, but he equally likes his food and a safe cosy place to sleep
The only difference that neutering made to my mum's cat who she's had since 9 weeks old, is that he got into marginally less fights. The other cat she got from Cats Protection at 1 year old so was pre-neutered. Both of them still go exploring and climbing high places.
My cat's neutered, has a large territory, hunts terrorises the local wildlife and beats up the neighbourhood cats despite now being a kitty OAP No guarantees you'll get a docile homebody if that's not his nature now!
Neutering only stops them roaming after females (I think)
Our kitten cat went out from six months, after being neutered, was up and down all the trees in the garden, calling for DH to help him get down and managed to get from one conifer onto the roof (bungalow),
One year later, he still goes on the roof and up all the trees but gets down himself, he goes over on the field for hours on end but has a curfew at 7pm in summer and as soon as its going dark in winter.
Much better for him. You should look at the figures on the average longevity of unneutered males. Male cats don't know about the concept of being a Dad (Mom hightails it afterwards) and neither would I anthromomorphize about the sex. Being a full tom is mainly about roaming around in the cold and having fights with other cats, I think.
You would feel far more mean if he was not neutered and then contracted a terminal illness from random sex with ferals, or comes home with half an ear missing because he fought a neighbourhood tom for the privilege! You are doing the right thing.
It could calm him a bit - but when I got my last ginger boy, I was coming downstairs one day and wondered what had been 'not quite right' about the neighbour-across-the-street's house when I glanced at it through a window. I dashed back up again to see the glorious silhouette of a cat in full stalk along the neighbour's ridge tiles. (And that was a two story house and not a garage.)
Unfortunately, roofs are where birds go because they feel safe up there. Poor deluded fools.
He may be more of a homebody after neutering but quite a lot of his behaviour won't change, I fear.
Sorry OP, neutering will stop him travelling for miles to find a calling female, but will do nothing to stop him being a cat!! .....climbing trees, exploring, hunting and looking for entertainment are all normal feline behaviours
Do keep him in a night though. It really is much safer for them.