The scriptures are very clear: we all make mistakes. Big mistakes hurt more, and generally longer. Uncorrected, they can hurt our children, grandchildren, even many generations into the future.

So, we repent. Simple word, simple process. Not easy. Not even close to easy. I look at my own life and see that I need to do more re-penting, prayerful re-thinking. It’s a sorrowful, joyful process. What the Church says is best found in Isaiah 1:18 (16-19). I know it is true.

A couple of times, I’ve had to go to my bishop for help in the process. It has been humbling, and helpful in directing my pondering and prayers.

President Packer has said “Nowhere is the generosity and kindness and mercy of God more manifest than in repentance.”

In the process of prayer, searching and pondering for answers, you’ll need to pour out your whole soul to your Father in heaven about your relationship with your SO. That’s a big, important decision.

God bless you forever.

In order to get through the process of repentance, faith needs to be strong. That’s why it’s so important to get a spiritual witness straight from God that the Church is true. So that’s the first step, and it’s achieved through personal prayer, and then trusting God when He says He will help you.

In order to qualify for baptism, yes, you’ll have to change your situation, and we all know how tough that is, when love and support, even financial support are all at stake. There are people who can help, and no one could be more helpful than your partner, should he also obtain a witness of the truthfulness of the gospel.

So the first step is to have an honest talk with your partner. Would he be willing to take lessons from the Mormon missionaries to see whether he could accept it? Will he be willing to pray about the things the missionaries teach him and the things he reads in the scriptures? Would he be willing to make the lifestyle changes necessary to become worthy for baptism?

Determining these things will help you make the decisions you personally need to make. One more help, the following are the steps of repentance:
First, to recognize that your behavior is against the commandments of God.
Second, to desire to bring your life in line with God’s desires. This could be called “reconciling yourself” with God.
Third, Ask God for help, and enlist the help of others along the way.
Fourth, restore that which you have stolen or damaged. Now this may sound impossible, and often it is. When we can’t restore what we’ve stolen or damaged, we can still apologize and seek forgiveness from someone we’ve offended.
Fifth, resolve not to commit the sin anymore.
Sixth, keep God’s commandments to the best of our ability.

As we follow these steps, we become more and more in tune to the Holy Spirit and direction from God. The Mormons you know who seem to have it all together are actually repenting all the time, as they find things in their life that offend God.

This is a process, and not instant change. Mormon missionaries can guide you much of the way, and then compassionate “home teachers” and “visiting teachers” from the LDS ward or branch where you live.

Good luck! Let me know if I can answer any other questions you may have.