March 2019... You have been married and been a GC holder for 42 months. 42 - 9 = 33 months being a GC holder and residing with your spouse. You could file in December and have the 3 years' living in marital union requirement. Or you can file now and argue for "Involuntary Separation" due to required travel for employment.
EDIT: You are allowed to file up to 90 days before the qualifying date. Therefore, you can file sometime this month (based on when in March 2019 is your "residence since" date) without needing to justify the 9 month's involuntary separation.
Gaynto reacted to SteveInBostonI130 in Applying for citizenship - 3 year rule