It is important to "Be One" in several circumstances: as a married couple, as an engaged couple, as a missionary companionship, or even as a member of a team. For the purposes of this article, I'll talk about a married couple, although the same principles apply in the other circumstances.
In a healthy relationship, both spouses want the best for each other. They love each other. They want each other to be happy. They want to contribute what they can in order to accomplish this. Sometimes the relationship can become strained. Often this is because they don't agree on some issue, and instead of resolving the disagreement, one or both make a decision that the other gets upset about. Over time the disagreement festers, other disagreements add to it, and they lead to straining the relationship more and more. Some disagreements don't have any significant effect once both "agree to disagree", but others affect the life of the other person in a significant way. This is generally the case with finances, place of residence, bearing and raising children, keeping a home organized, spending time together, and more.
What can you do to "be one" with someone when a disagreement impacts both of your lives in a significant way? This is the question I propose to answer.
Warning: The answer is for oneself and not to be applied to the other person because that would not be healthy. It's okay to hope that the other person will notice changes and follow the example, but to expect it or push for it is not advised. Okay, so what is the answer?
It all starts with love.
If you are not feeling a lot of love towards them at this moment, search within yourself and re-ignite the love you have for them. In some cases, this might be very difficult because you feel so much hurt. Pray for you to be able to feel the pure love of Christ towards them. Remember how you met. Remember what brought you close together. Remember good times together. Think about what you have in common including interests, goals, values, beliefs, etc. Think about what you appreciate, admire, respect, and love about them. Think about what you hope for your future with them. Think about their potential and who they really are inside.
Love will inspire you to think more about them than yourself. From 1 Cor. 13 we read, "Charity...seeketh not her own,..." Matt 16:25 states, "for whosoever will save his life shall lose it: and whosoever will lose his life for my sake shall find it." Mosiah 2:17 states, "...when ye are in service of your fellow beings ye are only in the service of your God." These scriptures help us see that in order to achieve true love, we need to be selfless, and lose ourselves in the service of others. In doing so, we will be blessed with a greater capacity to love and serve. We must be careful to not take on more than we can do, however, "for it is not requisite that a man should run faster than he has strength." (Mos. 4:27) Still, you are capable of doing much, maybe even more than you thought possible. By serving, your love will grow and strengthen.
Along with love, have faith in them. For some, it is easier to have faith in God than in someone who is imperfect and mortal just as yourself. In this case, have faith in them, trusting that God is helping and supporting them. Even when we make mistakes, God is there to help us pick up the pieces, and start again. Wouldn't it be better to do that together as one than to be divided? "Two are better than one;...for if they fall, the one will lift up his fellow: but woe unto him that is alone when he falleth; for he hath not another to help him up." (Eccl. 4:8-9)
The answer is to "go along for the ride." Allow them to discover the truth, with you by their side. Share your thoughts and ideas only when they actually want you to. If you're not sure whether they want to hear them, then ask them. Go along with what they want to do (even if you don't agree). When you notice their good ideas and successes, point them out. Support them in their struggles. Comfort them when they need it. If they look to you for validation of their feelings, do so. If they lack confidence in their ideas, encourage them, trying out the ideas with them. As they look to you for help, commit to do so, and follow through with your commitments as best you can. If you struggle, share your personal challenges and ask them (and even others) for advice. When things don't work out well, point out observations (not conclusions) and ask them for advice.
Through love and faith in them, you can "be one" with someone else, even when you don't agree on issues that impact both of your lives in a significant way.