Need opinions (be nice)

So I found out that I'm 5weeks and 3 days! So excited! But I have a problem... Aug 30 was my lmp and it said I conceived the 13/14 of Sept. My husband and I had sex all the week up until the 15th the early hours of 16th I got super drunk and slept with my friend.( 3 weeks ago today ) Whats the percentage of it being my husbands? Yes they both know yes everything is fine I'm just curious, I'm 100% it's my husbands but I want to be sure