I have to say I've been doing sw a long time and when me and my bf moved in together last year I was worried that my eating would go out of control , but it hasn't.
I only cook sw meals and if he wants extras with it (sauces, cheese, bread) then he does. We only buy sugar free fizzy pop, and when he has 'treats' I either syn it or whip up something of my own. I've even got him cooking sw way and he love sw curries.
We've got an amazing balance, but I do have to use all the willpower I own sometimes!!! And more!!