LOL! Brian and I have been doing the 'living in sin' thing for about two years now. We are leaving in about 30 minutes to go talk to the priest (we set the date with him and are going in for the 'are you really sure you want to do this' talk and to get the info on what we need to do before the wedding - pre-cana, paperwork, rehearsal etc.).
As for her moving in with you, I suggest being honest, but I know that doesn't work with all women. I lived by myself for a year and a half before living with the Brain. I loved it. Brian's friend tried begging him to let him move in with Brain (so he didn't have to live at home) and his gf would accept that if he did, she wasn't going to be moving in so Brain put the kabosh on the whole thing. It also helped him to make his decision that I told him if his friend did it would be over between us because we both knew damned well his buddy's gf would be there 24/7. (I had issues with that because she was already trying to break us up and I wasn't going to endure putting up with her skank ass while visiting with him. )