As a pro-life person who also believes abortion to be a form of murder...

First, I am terribly sorry for your past. As much as abortion sickens me, rape does equally, if not more.

Second, I will keep my own opinions on the matter seperate, not only because it is against the rules of the sub, but because it would be a fruitless and pointless venture.

Last, please tell your boyfriend. It would be one thing if you had mixed feelings about it or regretted it and were wanting to discuss it. From what I read, you had it and have no regrets, and that's a big deal. While you may not view it as a big deal, to someone like me and others that view it as morally wrong, to not share would be not unlike someone who committed murder and regretted nothing about it and didn't want to share that with an SO. (yes, I know that analogy may seem offensive, but it's pretty accurate depending on who you are talking with.) You are free to understand morality as you wish, but so does your boyfriend, and not telling him will only give him even greater reason to be upset when he finds out.

The alternative (which I wouldn't recommend) is to just end it and not tell him why beyond "I have very differing views on x and y." I would only recommend this if you wanted his perspective of you to remain "untarnished" so to speak. At the same time, even if I disagree with someone, I can't expect them to hide their intents or actions.

If he blows up and is angry, please understand that moral outrage does that to people. If he blows up and is angry and treats you like a jerk, then good riddance. There are right and wrong ways to stand up your your morals.

Source - A Christian minister who dated a girl who helped a friend have an abortion before I met her.