
Quoting
llworking
It won't automatically cause you to lose custody, but it definitely will not help you keep primary custody either. The general feeling is that if a child can be in the primary physical custody of a parent most of the time, rather than a third party, that its in the child's best interest to be with the parent.
Your child would be being raised by your wife rather than by either of her parents if you take that job. Your wife is not her parent just as mom's husband is not her parent either.
By the way, from your description of mom's living arrangements for the last 7 years it does sound like mom is married to a military man and that is the reason for the frequent moves. If that is the case, you need to say so when explaining things to people. Otherwise it could make you seem as though you are trying to make mom appear as unstable, when in reality the moves have nothing to do with instability.