Question:My girlfriend and I had sex outside of wedlock and I was wandering what I needed to do. I am ashamed of it and I'm not sure what to do. I have trouble sleeping at night cause I keep thinking about it. I think if I repent of it and change my ways I should be fine, but I'm not sure. My girlfriend also had a child out of wedlock before we had sex, but the guy cheated on her and left her, but I think she has repented for it though. My question is what do we need to do because we had sex? Also is it right for me to marry her because of her child out of wedlock? Or do I need to because we had sex? I am in a big mess and I'm not sure what to do. Please help me as soon as possible. Thanks.
Strangely enough, it is a good sign that what you did bothered you. It is the people who seem to be unaffected by their sins who are the most difficult to help. "'Were they ashamed when they had committed abomination? No! They were not at all ashamed; Nor did they know how to blush. Therefore they shall fall among those who fall; At the time I punish them, They shall be cast down,' says the LORD" (Jeremiah 6:15).
Your case is one where I wish we could sit down and talk through the situation in detail. I can tell there is much more going on that just the problem you outlined. But let's work through the problems a bit at a time -- just realize that I am making several guesses about the situation. Please feel free to clarify it, especially if I missed the mark.
You realize that what you and your girlfriend did was wrong. "Marriage is honorable among all, and the bed undefiled; but fornicators and adulterers God will judge" (Hebrews 13:4). Any sin, not just fornication but any sin, needs to be both corrected and forgiven. I don't know your background. I don't know if you have obeyed God's commands to become one of His children, or if you only pretend to be a Christian by claiming something without actually obeying God. Too many denominations only teach a part of what God asks of His people. As a result there are many people who think they are Christians, but they never became a part of His covenant. I would like you to read through all the verses in "Things That Accompany Salvation" and let me know if you have done all of what God commands. If you haven't, then that is your top priority. Only God's children get into heaven, so I need you to be a true child of the heavenly Father.
In regards to this particular sin, you are correct that repentance is required. But repentance is not just feeling sorry for what you have done. Repentance begins with being sorry because that sorrow is what spurs you to make changes in your life. But the sorrow itself is not the repentance. "Now I rejoice, not that you were made sorry, but that your sorrow led to repentance. For you were made sorry in a godly manner, that you might suffer loss from us in nothing. For godly sorrow produces repentance leading to salvation, not to be regretted; but the sorrow of the world produces death. For observe this very thing, that you sorrowed in a godly manner: What diligence it produced in you, what clearing of yourselves, what indignation, what fear, what vehement desire, what zeal, what vindication! In all things you proved yourselves to be clear in this matter" (II Corinthians 7:9-11). Repentance means that you change your behavior. It might seem obvious, but a part of changing is that you must understand and face what you did wrong and why you did so. It is common for people to say that a certain action is wrong, but they have trouble owning up to why they did it. As an example, there are a lot of people in jail for stealing who can tell you that stealing is wrong and that they are sorry that they stole the item that put them in jail, but they don't change. Why? Because they have a long list of "reasons" why it really wasn't their fault. They are sorry that they were caught, but when they get out, they will soon repeat their sins because they gave themselves a license to sin by their excuses.
This is one aspect of the idea of confession, looking into your heart, stripping away all the excuses, and seeing both what you did and why you did it. "If we say that we have no sin, we deceive ourselves, and the truth is not in us. If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness. If we say that we have not sinned, we make Him a liar, and His word is not in us" (I John 1:8-10). This is often hard to do alone because we don't often see our own deceptions. "Confess your trespasses to one another, and pray for one another, that you may be healed" (James 5:16). What I would like you to do is think about exactly what you did and why you did it. If you knew that fornication is wrong, why didn't that knowledge stop you? None of this "it just happened" type of excuse. Sex doesn't just happen.
Once you know why sin occurred, then you can face where your weakness is in regards to this sin. Only then can you truly repent; that is, only then can you take action to minimize the possibility of repeating the same error. You stated that you think your girlfriend had repented of her sin of having a child out-of-wedlock. I don't know her, but I wonder why you come to that conclusion. She lived with a man, had a child with a man, all without being bound to this man in a marriage, and then when that man left her for another woman, ends up having sex with you. I'm sure she was upset that this other fellow left her, but how did her behavior change?
Whether it is right for you to marry this woman or not has nothing to do with whether she has prior children. The question is do you love her? At the moment you probably believe you do, but that is only because of your sexual activity. "Or do you not know that he who is joined to a harlot is one body with her? For "the two," He says, "shall become one flesh"" (I Corinthians 6:16). I've been amazed over the years how many young men have no clue as to what love -- true love -- really is. Take a look at the article "Love Is ..." and see if this really describes your situation. I suspect that you will find that many of the items listed don't match your current relationship. It is not that true love can't exist between the two of you, but I know it doesn't currently exist. Why? Because you involved her in sin that can send both of your souls to hell if it is not fixed. If you truly loved her, you would not do something that would jeopardize her relationship with God.
The fact that you sinned with this woman by putting your penis where it doesn't belong is not reason to marry her. If anything, it is reason to say that you have a lot of work to do before you are ready for the responsibilities of marriage. You don't fix a sin by piling more wrongs on top of it. "And why not say, "Let us do evil that good may come"? --as we are slanderously reported and as some affirm that we say. Their condemnation is just" (Romans 3:8). It would be wrong to marry a woman whom you do not truly love. Get things in the proper order first. Build a loving relationship, then get married.
One last thing, on a more mundane level but still necessary. You need to see your doctor. Tell him that you had sex and need to be check for sexually transmitted diseases. There are a LOT of diseases which have little to no symptoms until they cause permanent damage to your body. You have no idea what diseases your girlfriend has or was exposed to. You can't even judge it by how many men she has had sex with because we know that at least one of her partners has had multiple sexual partners. We don't know how many diseases he was carrying and then you put your penis where he had been. "Whoever commits adultery with a woman lacks understanding; he who does so destroys his own soul. Wounds and dishonor he will get, and his reproach will not be wiped away" (Proverbs 6:32-33).