I think my boyfriend accidentally got me pregnant
What do you mean when you say accident?
Because he has already cheated on me 3 times and because we haven't used protection.
I'm sorry he cheated on you and that a pregnancy came around during all of this. I hope you can stay strong and that he can wisen up to help take care of this child.
I did the math again, and I think I might not be pregnant after all, maybe 99% certain.
Pregnant or not, you should not put up with what he did to you. He should tell you if he is using protection or not.