Same queston pregnancy ultrasound?

please dont judge. stopped taking bc the 1st of feb. had sex with bf somewhere between 1st-15th of feb (not sure exact). had sex with another guy march 4th. ultrasound on 22 of april stated i was 9wks 1 day. and my duedate is nov23. on conception calculator it states conception between feb 26 and march 6. cause gestational age adds 2 weeks so at 9 wks gestation, fetal age (from conception) was 7 weeks. i am about 11 wks now. how accurate is all that and is other guy or bf more likely the father?