Cyberstalking

I just wondered if anyone knows much about cyberstalking? Sorry, I know this isn't a techy forum. My XP had my wireless key and I wondered if he might be able to hack or tell when my wireless is on (I turn everything off when I go out or am away). I realise of course he could sit outside but is there another way. He's got loads of money so could probably afford to do alot. It might not be a good idea to post on this (not wanting to give the bastards any ideas), could someone PM me? Really, really grateful for any help.