Unable To Marry Fiance From Selvadorada

My Sim met a vendor and hit it off as well. Her first day back there was no option to invite him (only chat and text were available), so I had her send him a love email. After a day he called and asked her out on a date, they went to a restaurant and I got their friendship & romance up a bit more. At that point I was then able to travel with him and invite him over, I haven't moved him in yet but the option is available now. I would say try sending a love email, or just calling and chatting a bunch until the vendor invites your sim somewhere. The only other thing I did was cheat him into CAS to change his facial hair (that might have been after the other options were there though).