I work for a big US-based IT firm in a project that requires special skill that I possess due to my particular type of education. I used to work in one of their international offices (say Paris) and was doing very well, collaborating on very good terms with my counterparts in the US. Eventually, they offered me a position in their headquarters at the US for the same work but reporting to a different manager. Personally and career-wise, it is a very good move and I, after discussing with my spouse, have decided to take it up.
The catch is that my spouse will also have to leave her current job and look for a new one in the US. An easier way to do so (rather than coming to US as my dependent and finding a job which has lot of complications) is to find a firm in Paris based out of US and has the facility of transferring their employees to US on their own independent visa (similar to what I was offered). So she started looking for openings in Paris in US-based IT firms which have an office in Paris and can transfer employees to US. Now, my previous manager at Paris (as I now report to the US manager), who is on very good terms with me and still works closely with me, is looking for a replacement for me. By a funny turn of fate, now my spouse is being interviewed for this position and it looks like she might clear.
Unfortunately, my old manager doesn't know that the original reason that my spouse is looking forward to this opportunity is to transfer to the US. Now my old manager may not make an offer (I presume) if he knows that in advance, as he will end up in the same situation (similar to losing me) after a year or so. It's pretty difficult to find candidates for this position and my old manager wouldn't want to be in a situation where he is recruiting and ramping up an employee only to transfer them to a different place.
Am I obligated to reveal to my old manager (given our good relation) that the candidate who seems to be good to replace me is my spouse and that my spouse intends to move out after a while (which is sort of obvious anyways)? I was not involved in the interview process or the referral process anyway.
PS: I met my spouse during our graduate studies for this special skill which is why we both are in same domain.