If all scan dates point to a certain cycle is it safe to say I conceived that cycle?

I had a heavy bleed beginning of December 5/6th but had intercourses 3 days prior with a friend, then again 2.5 weeks later with my ex after my period.

All dates point to my ex but there is still nagging doubt. I had an early scan and if it was my friends baby I would of been 2 weeks further gone (taken sperms life span into consideration).

I know DNA is an option but all evidence points to my ex even the conception indicator lined up with scan.

Please no judgement I was in a very vulnerable place during this time and in no way want to offend anyone.

My friend is African and my ex is white

I have a 4D scan done and can’t help but think my baby looked mixed, my anxiety is that bad I am obsessing over it 😢

I know it’s my own fault but I just don’t know what to think.

Due date 13th September

Thank you x