Boyfriend

So my period hasnt come yet its a day late and its on time all the time so i told my boyfriend and he was like im not ready for a kid you should get an abortion witch i would never do and he knows tht and now hes blaming me saying that i begged him and forced him to cum in me and i didnt he just did he didnt pull out i dont think i should be the one to blame if i am pregnant we both had sex and he wasnon top everytime he could of pulled out i dint force him into cumming in me i feel really upset about this should i be the one to blame an he knew i was on birth control am i in the wrong for being upset??