I cannot find the S5560 on Samsung's website. However neither the S5500 and the S5600 have the ability to use wi-fi. Wi-fi connectivity is still quite a high-end feature for mobile phones and many don't have it. So just because you can use the internet on the phone, doesn't mean you can use your home wifi with it. The type of signal home wi-fi uses is very different to and EDGE or 3G signal that a phone will normally receive.
Of course, if your hubby has the same phone, then there obviously a problem, but it doesn't sound like he does. So I reckons you're stuck there.