Some thoughts for the partner who is in a relationship whose mate has been unfaithful:

God's Word makes it clear that marriage is a covenant - between God and man kind and that marriage is a commitment for life to the one individual chosen to be one's mate. 

This commitment means that "we forsake all others" " For this reason a man will leave his father and mother and be united to his wife, and the two will become one flesh." Matt 195 NIV

OK, but what if this beautiful plan of God has been shattered by unfaithfulness ?

Sexual unfaithfulness, however, on the part of both husbands and wives, has become epidemic, according to polls and reports on sexual practices.
Hebrew 13:4 , 1 Corinthians 69-10 and 1 Corinthians 618 are some of the scriptures that deal with the marriage issue and immorality.

Let me say this, ADULTERY is not a command that you have to get a divorce. If it be at all possible to work out the marriage then by all means at least try. With God's help and the man and woman cooperating with God's Word and the Holy Spirit the marriage can be salvaged.

Here are some of the consequences:

Emotional guilt, fear, anxiety, loss of self-esteem, shattered personalities, depressions, feelings of being in competition, anger, frustration, desire to hurt back or get even, AIDS and other sexual venereal diseases that can be life threatening ......

Physical illegitimate pregnancies and births,  and abortions, loss of mate and family

Spiritual loss in this life and in that which is to come. Feelings of rejections, unclean, lowest of low.

Is there HOPE ?       YES !

Let's get started

We know that adultery is a sin.
There are many reasons for adultery:

1. Our own sinful, selfish desires. James 1:14
2. Lack of maturity.
50% of teen-age marriages come apart in the first five years, however age is not the only criterion. Immature selfishness at any age can lead to unfaithfulness. Another sign of immaturity is a lack of willingness to accept the responsibility of a family.
3. Demanding, critical, scolding, nagging husbands and wives
4. Lack of sexual satisfaction on the part of either mate.
5. Transferring to one's mate hostility felt towards a mother or father.
6. Meddlesome in-laws who smother a husband or wife with criticism or well-intentioned advice.
7. Lack of adequate sex education
8. Drugs and alcohol many times place an important part
9. Pornography can also lead to unfaithfulness
10. Internet chat rooms, and web sites that promote like actions,
11. Abuse, 
12. Constant comparing of the mate to someone else making them feel inadequate,

And the lists go on and on,    Etc......

You should expect no easy solutions in dealing with the problem of adultery. It will take a lot of hard work on you and your unfaithful mate.
The first this is to see your unfaithful mate as your mate and not as the unfaithful mate. Many couples make a lot of mistakes in their marriage and adultery is at the top of the list. Even the act of adultery can be forgiven.

Jesus Christ showed us that with the story of the woman caught in adultery, who was cast down at his feet ( even thought both man and woman should have been - not just the woman- it takes two to tango they say ) 
But Christ forgave her and said, "Sin no more". He literally gave her life back to her but this time with the option of living it in the view of God's divine will for man kind.

However, God can work a miracle of the new birth for the non-Christian and the spiritual renewal for His own who have fallen away. 

If you and or your mate are successful in securing a commitment to Christ, you can be confident that this will bring a new perspective making it easier to mend lives and to reach permanent solutions.

Here is some help for you

When you are the partner of the adulterer, you often feel betrayed, rejected and hurt. Although only one person may be guilty of unfaithfulness, often both partners in a marriage CONTRIBUTE to it.

You must be on the healing side of this, not the attacking side.

1. Encourage the person involved in the adultery to answer just a few questions:

A. How may I have contributed to my mate's infidelity?

Am I Critical? Supportive? Have I been a work-a-holic? Have I neglected your cries of loneliness?

Have I been more of a parent figure than a mate? Have I failed to show you the romance you were needing?

B. What circumstances have been present in our marriage which might have contributed to the problem? Parents? Ignorance? Drugs, Work schedules, absences from home?

C. How may I help to provide a solution to save our relationship?

( Never ask - Tell me everything you two did together - this will only eat at your mind and will drive a barrier between you and your mate that will be even deeper because you will not only feel more hurt, but you will feel that you are always competing to be better. This knowledge will be like a CANCER that spreads very quickly. Every time you two have sexual experiences it will eat at your mind whether your partner is remembering or reliving that same sexual experiences in their minds with some one else. It only weakens the relationship when you do this even more.)

2. Help the inquirer to determine the best course of action

A. Forgiveness. Things can never be worked out unless there is forgiveness. This may be very difficult, but a way can be found if you truly love your mate and want to spend the rest of your lives together.

You can not heal the marriage if you always look at your mate as the adulterer.   You have to change the way you see that person. To forgive is to see that person as your mate, not as a mate who broke your heart. This takes a lot of work on your part and your mates part. With the power of the Holy Spirit, your renewed commitment to each other and to Christ you can do this.

Those involved must ask for God's grace and wisdom to face it. Your love and concern will be most evident at this point. The guilty spouse must also seek God's forgiveness and the spouse's forgives.

B. Communication The couple must make a determined effort to communicate with each other in order to discuss freely all facets of the issue. Lack of communication may have been a contributing factor to the problem. Now is the time to correct this.

C. Prayer The couple should pray together and trust God to work things out so that the marriage may be saved and grow stronger.

D. Counseling They should be willing to consider serious professional counseling with a qualified pastor or a Christian psychologist or psychiatrist. It may take time to work things out.

SCRIPTURE:

1 John 1:9 KJV " If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness."

St. John 8:11(KJV) "She said, No man, Lord. And Jesus said unto her, Neither do I condemn thee: go, and sin no more."

Hebrews 13:4(KJV) Marriage is honorable in all, and the bed undefiled: but whoremongers and adulterers God will judge.

1 Corinthians 7:3-4(KJV) Let the husband render unto the wife due benevolence: and likewise also the wife unto the husband.(4) The wife hath not power of her own body, but the husband: and likewise also the husband hath not power of his own body, but the wife.

Isaiah 1:16-18(16) Wash you, make you clean; put away the evil of your doings from before mine eyes; cease to do evil;(17) Learn to do well; seek judgment, relieve the oppressed, judge the fatherless, plead for the widow.(18) Come now, and let us reason together, saith the LORD: though your sins be as scarlet, they shall be as white as snow; though they be red like crimson, they shall be as wool.

1 Corinthians 6:15-20(15 KJV) Know ye not that your bodies are the members of Christ? shall I then take the members of Christ, and make them the members of an harlot? God forbid.(16) What? know ye not that he which is joined to an harlot is one body? for two, saith he, shall be one flesh.(17) But he that is joined unto the Lord is one spirit.(18) Flee fornication. Every sin that a man doeth is without the body; but he that committeth fornication sinneth against his own body.(19) What? know ye not that your body is the temple of the Holy Ghost which is in you, which ye have of God, and ye are not your own?(20) For ye are bought with a price: therefore glorify God in your body, and in your spirit, which are God's.

At least this is a starting place. You can not heal your marriage until you at least start the healing process.