With the recent news of a well known site being hacked into by a 'Hacktivist' group and holding their records over their heads ....
You can never be too careful with the information anyone gives out, even ladies.
A separate e-mail, private browser, separate computer, and even changing passwords often is of no help if you leave the browser open, computer unattended .... All it takes is a quick glance at it from a SO.
With that said, all of what was said in OP is something which everyone who have a SO should adhere to strictly to the point of an OCD.
Personally I use a separate E-Mail and IM to distinguish between the real life and this one, and I try to double check the correct e-mail account I send e-mails from too.
Any electronic medium message are kept for years even after they are sent and deleted from yours and recipient's folders / trash. Hard drive / storage is cheap and better compression algorithms are developed yearly. The 'only' way left to keep things 'private' is snail mail, even then it may get lost or misdirected.
The next best way to keep things a 'secret' is to attend a m&g and exchange information directly and discretely.
