male cat isn’t interested

for context we are NOT trying to breed that cats! we are unable to get them both done at the moment so it’s a save in grave really but we don’t understand what’s happening? 😅

me and my s/o just moved in together and obviously we brought our cats. my female cat just came into heat, showing all your usual signs etc and he have an 11 month old boy cat. my female cat is turning 3 at the end of this year and she’s never shown these signs before, we moved in together at the beginning of October and now she’s come into heat.

shes constantly rubbing herself along him obviously wanting to mate, but our boy cat isn’t even batting an eyelid? he just moves away. could anyone know why he doesn’t seem to be bothered about the fact she’s in heat?

again, we are not trying to breed. the whole situation just doesn’t make sense so wondering if anyone knows why?