pregnant help

so me & my guy had stopped talking for about 10 days.. in those 10 days i had sex with someone else (24 25 26th of july) my fertile window started the 25 & then starting the 27th me & my guy started tlking again and have been inseparable since.. weve had sex evey day since. well i was suppose to get my period this past week and it never came, i took a pregnancy test & i am positive my man & i had sex on my highest days of fertility and 110% def did cum in me. the other dude i am not so sure bc every time wed have sex itd be too long and he wouldnt cum... so my question is, is the baby more then likely my mans? my boobs started killing me 1 week ago and still do and i have no other signs of being pregnant other then being tired and maybe irritable.