Good decision, apart from anything else, he's likely to pick up feline leukaemia or feline HIV if you don't have him neutered.

(These can be caught by fighting or mating )

We had a male cat for about 10 years, who didn't have his family jewels removed.

He never sprayed in the house, and seldom came home injured from fighting (certainly no more than de-nutted cats belonging to friends), so I'm guessing he either didn't fight much, or he won pretty well all the time.

It's also claimed that de-nutting stops them spending all night out during the mating season, yet he still spent plenty of nights out.