My wife just came back from oversea after one month having a course. I was surprise when she told me she want to have anal sex with me for the first time, and when we did she somehow moaned another man's name...Is there any possible reason?

Probably not a good thing, but could just be harmless. She was possibly just living out a fantasy. You could try confronting her, and if she gets really defensive then you have your answer.

Lot's of reasons and i can't think of one good one. If my other says another persons name.....she is no longer my other. Period.

I suspect she probably got talking about anal sex overseas and she came back wanting you in her ass. That is a good thing as she is exploring her sexuality with you.

Moaning another persons name is probably your imagination. Don't look for trouble where there isn't trouble.

I say give her cock in her ass hard and see how she reacts. If she gets to like it then you win by having the new act of sex in your repetoire.

Keep a keen eye out for her cheating, but otherwise enjoy your anal sex and have fun! Don't make up problems where there isn't any.

LOL

She been fucking another dude. sorry man, but hey. she wants to do anal now! look at the good side of that, she probably tried it when she was away and liked it. good luck sorting out any problems you might have with all that.

Yes, you were not there at that time...
will you do the same if you were the one alone for a month oversea ?

The first reason that springs to mind is that she had a lover overseas, and that she had him take her anally so that she could deceive herself that she hadn't REALLY become an adulteress.
I'd have to presume that you have been cuckolded.

It could be she is just fantasizing about a long ago past lover. Anything can trigger past memories, especially in the heat of the moment.