The thing is, that assumes a happy, loving relationship in which you can trust your partner not to try to prevent you, guilt trip you, punish you or shame you. Which, if that was the case, you probably wouldn't feel the need to keep it from them in the first place, and certainly wouldn't be asking a group of strangers for permission.
What I think is being debated here is whether the potential father has a right to know about an abortion, regardless of the sitution. There is sometimes an idea that "it's his baby too!" and thus a woman does something unspeakably immoral if she decides not to tell the potential father about an abortion, even if it might put her at risk to do so.
However, this is often just another way to shame women for daring to get an abortion - the idea there is a "right" way and a "wrong" way, and the right way includes owning up to your shameful secret.
Personally, I think if more men knew how many times their ass has been saved by an abortion, they might regard it as a more important public health issue, but that is a best-case scenario - if a woman decides that the individual man who has contributed his sperm to her pregnancy is not someone she wants knowing about her abortion, then that is the end of it. None of his business.