Sim return from trip to China married to Sim there

[Janna]

looked for previous discussions, couldn't find any. 
My sim, who has the eternally faithful to her sim, went to China and when she came back she was married to a man from China!  Her last name had changed and he was listed in the family tree as her husband.  She still has her real husband and is still eternally faithful; it looks as if she married Pei, then left him to be with Jaques and kept Pei's name. 

I went back to the saves I had in China, hoping it was before the "marriage" but they showed her married.  She didn't go to the city, she started off hunting for the five metals, dropped them off.  It wasn't Pei who she gave them to, and before she could do the new adventure it was time to go home.  The only other sims she taked to were at base camp.  I checked relationships and he was there in the llst of sims. 

Tol get her unmarried, I had to restart her from the game before she left for China.  I deleted all of the ones of her visit to China, it seems she was "married" to Pei as soon as she arrived.     

Any suggestions on how to deal with this next time, if it ever happens again?  I tried to do the name change at city hall and I couldn't, that option wouldn't show up.   

[Schipperke]

I've never had a Sim come home married, but I've had them return from travelling with the family tree listing a new child with someone they never even met.  The only way I know of dealing with these annoying travel bugs is to save before you travel and save under a different name when you're abroad, so that if necessary you can return to the pre-travel file.

[Pam]

I've heard of the coming home married thing.  It's got to be part of the well known travel bug.  I thought it had been at least partially fixed with one of the recent patches.  Is your game fully updated?

[Janna]

Yes, I stay up to date on the patches, so that shouldn't be the problem.  I guess a hicup, maybe?

I make a point lof saving before I leave for a visit so I was able to go back to the place before the trip.  It was just aggrevating to lose everything I had gained.  It wouldn't have been so bad if it has been at the end and I had the saves from during the game, but the  marriage has to have happened as soon as she arrived. 

Part of playing games; if it can happen, it will.  I'm just making sure to save a LOT, as everyone states.