Okay... It sounds like you have decided to keep it. I hope you understand that (in most countries) you do not have to. I've never regretted terminating my pregnancy... But I'm not here to try and convince you. It is your choice.

Now regarding telling him that you are going to have his baby and "ruin his life": There are actually two schools on this. Neither is intrinsically right or wrong... Just consider both options and decide which one fits.

1.) By having sex with you, he assumed responsibility to potentially care for a child that should come from BC failure.

In this one, you would explain that you are both responsible for this and he will need to help support the child. Hopefully your relationship will work out for a while and you can do this together But if not, you will just collect child support and hopefully work out agreeable custody agreements.

2.) Having protected sex with you without first agreeing that you would keep the baby in the case of accidental does NOT entitle you to his support should you get pregnant and decide to keep the pregnancy against his wishes.

If this is the case, you have the option to not ruin his life. You will keep the pregnancy with full understanding that this is your choice and your choice alone to have the baby rather than terminate it. You will raise it on your own or with support of your family and he can sign his rights away of he wishes.

It really is your choice. Just like he can't force you to keep it since you never consented to carry his child before having sex....You can't force him to father a child he doesn't want. (Under this philosophy).