I'm guessing that your problem isn't so much that your data is being saved w/o the line breaks as it is that when displayed the HTML does what HTML does and ignores those line breaks and extra whitespace when displayed.
You can fix this by replacing the line breaks with a <br> using the str_replace method. Either before storing the data in the database, or after you read the data from the database and before you display it...
Something like:
Code:
$sFormattedString = str_replace("\n", "<br>", $sOriginalString);