Old issues -- ones neither of you may even realize are there, influencing your behavior and attitudes about relationships -- come to the surface during this two-to-three-year transit, forcing you to face them down and deal with them, no matter how difficult that process might be. Perhaps you watched your parents go through a loveless relationship, or a bitter breakup; maybe you've each been through your own bad experiences in the game of love. Wherever these issues originate, they're still affecting you now, and inhibiting the ways in which you connect with each other now.
Couples therapy might be very effective now in helping you to work together through some of these old, buried problems. Otherwise, reading self-help books and making an effort to talk out your feelings, dreams and memories together could also be a big help. But in some way, you should both make a combined effort to process through these issues. Otherwise, this could be an even more difficult period for your relationship, as you each try to manipulate and control each other in a bid to keep things the same between you. But things are changing, and you should change with them.