Feeling really guilty??am i crazy?

Okay i am 27 yrs old and my hubby is 35 we have been married for a over 6 yrs.My husband had an affair with his secretary the second year of our marriage i was very angry. The relationship with my hubby went pretty cold after the affair.A little while later while i was getting my car fixed i ran into an ex.bf from highschool we got to talking turns out he was the owner of the shop.We talked became friends and i started bringing my car by more and more.An affair happened and i ended it started going to therapy with my hubby.Turns out i was pregnant during this time i gave birth too twins my relationship with my hubby returned to a so so level.I never really questioned my childrens paternity because the last time i had sex during the affair as the last day of my cycle. But now i am worried my hubby and i have dark brown hair/eyes my daughter has dirrty blond hair/hazel eyes.Could this just be guilt?