It is simply the position of Moon which is in Sashtashtama dosha. There are 8 other planets in the horoscope and if they match well there is no problem. Read my article “Astrology – A new version” on my blog and another detailed article of which there is a link, you will understand how to establish a full compatibility of all nine planets in the horoscopes between you two. Do not believe the way side astrologers who know only how to look at Moon compatibility in isolation and decide matters. It is like buying a car looking at its paint without considering the aero dynamics, engine capacity, and many other characteristics like what mileage you get and safety measures included etc. which must be looked into.
Shastashtama is not such a dosha contributed by the planet Moon only. There are nine planets in your horoscope and just because one planet is having a problem, it does not mean there is no match between the horoscopes. Read my blog navagrahastro.blogspot.in articles “Marriage failures-How astrology can help” for more details.