Low fertility day

How likely is it, honestly, to get pregnant on a low fertility day? I'm 6 days from my next period and hubby decided last night of all night was the time to not pull out🙄 I have been telling him for months that I was ready to start trying for number 2 and he kept saying he didnt want another baby but this last week he has said maybe soon.. I know its very unlikely that I got pregnant last night I'm just curious as to how likely it is past your peak day.