"Honest without shaming"...I'll answer carefully, then. If it was a situation where we'd been estranged, I became involved with someone else and after we reconciled I discovered I was pregnant, I would tell him. It would be too difficult having the question of paternity hanging over our heads. And imo, he'd have the right to know whether or not it was his child.
Complicated issue. AS preface, I'll say I strongly beleive in a woman's right to take pleasure with whoever she wants, wherever she wants, when she wants.
I DO NOT believe it's okay for a woman to entrap a man in a support situation with a child not of his own making. . .
If they're married or in a "permanant" relationship, and he wants a child, and if he isn't emotionally able to hear about it being someone else's, maybe it's kinder to say nothing. But ideally, any sound relationship is built on complete honesty.
There was a study done a while ago that estimates about 33% of men are raising kids that are not biologically theirs. Don't know if that's gone up or down recently.