https://news.bbc.co.uk/1/hi/health/8125934.stm
This is a link to the BBC News website which has the same story. Before you tell your partners the good news though, this doesn't apply to all of us!
The sperm apparently deteriorate the longer they hang around so it's been suggested that having sex every day means you get them while they're still good. However, it says this only applies to men with normal counts - if the problem is low SC the advice remains as it was before, every 2 to 3 days is best.