During the several years of this transit you may experience an increase in your defensiveness with each other, which could lead to more arguments than usual. You're both feeling somewhat vulnerable, because you're going through a process of intense change in the way that you think about the relationship, your lives, the love that you share -- all the big things that you may have thought you had all figured out. But now, big truths you've been ignoring are staring you in the face, challenging you to face up to them.
You may each find that you've been operating under certain assumptions regarding the relationship, or romantic relationships in general, that just aren't true. If so, you'll have to talk things out together, which could be difficult; you're both much more apt to argue now than to discuss touchy subjects in any calm, rational manner. Counseling may be a good idea now, if you're open to it and interested; it could be a huge help to have a professional mediator there to help you wade through your confusing jumble of thoughts, perceptions and influences. Just know that if you come through this period intact as a couple, you've done some hard and important work!