 If you liked
I Accidentally Saved the Male Lead's Brother
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 ...then you might like
Becoming a Family With the Duke and His Dear Son
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By the same author, with the same 'female lead + cute adorable children related to someone of high stature who will inevitably fall in love with her' character dynamic.
There's also another manhwa by the same author that's even more similar to this called "I Didn't Lull You to Sleep Only for You to Become Obsessed with Me", but it's not listed in MAL. Down to having yet another pink haired blue eyes female lead who left her shitty "family" and get together with the male lead.