As pp have said, this a question you only know the answer to if you're put in that situation. I have an IUD and would take the morning after pill but I suppose anything's possible.
That being said, I'm about 85% sure I would keep the baby. However, I have no idea how dh would feel and the baby would likely not be the same race as him (he is Asian and the vast majority of teh population here is white, then black, quite a few hispanics, but very few asians) and that would complicate things. I don't pray, but in this case I would pray, pray, pray that the baby would look like me. Dd1 looks NOTHING like me and completely like her daddy. Complete strangers would come up to me and say "she must look like her daddy, cause she sure doesn't look like you!" and that would be extremely hard for me emotionally.
I'm about as confidant as I can be that I would not terminate but again, who really knows what you would do when put in such a situation.
I would seek a counselor and psychologist's advice on when and what way is the best to tell my child how s/he came to be.