Many things could be responsible for your girlfriend's infidelity. Perhaps she felt her emotional needs weren't being met, or perhaps her curiosity got the best of her. In either case, if she's willing to ask for forgiveness, and you're willing to forgive, the relationship can survive. However, even after the apology, you might have difficulty trusting your girlfriend. If you really want to restore happiness and health to your relationship, you will need to learn strategies to open yourself to trust again.

Know When to Trust

Before you begin to trust your girlfriend again, you must make sure it's safe to do so. Look for signs that she is sincere and you are truly ready to forgive. For example, communication should be open and relaxed, secrets should be divulged and you should both feel like you're on the same team, suggests Susie and Otto Collins, relationship coaches, in their Your Tango article "Four Ways to Know It's Safe to Trust Again After the Affair."

Let It Go

Even if you still have some fears, forgiveness means letting go of your grudge. Don't refer back to the incident again or use it against your girlfriend, even if seems to give you a sense of power during arguments, suggests clinical psychologist Ryan Howes in his "Psychology Today" article "Four Elements of Forgiveness." For example, the next time you are inconsiderate and she complains, resist the temptation to throw her infidelity in her face. These past problems will only stir resentment in both of you.

Don't Take It Personally

It might be difficult to believe, but it's unlikely your girlfriend cheated on you out spite, suggests Marina Pearson, divorce recovery coach, in her Your Tango article "Five Ways You Can Learn To Trust Again After Infidelity." Don't view her actions as a personal attack on you. It's doubtful she desired to hurt you, although in the end she did. If you view cheating as a form of personal attack, you might be tempted to strike back, whether through infidelity or general meanness.

Address Insecurities

Learning to trust again requires you to clear your own mind of insecurities, suggests Pearson. This infidelity might have damaged your confidence, but learn to trust and nurture yourself again. Address bouts of jealousy and anger with a rational mind. Keep a positive self-image by diving into your hobbies, exploring new ones and staying social. Trust that you are worthy of love, and you will have an easier time trusting your girlfriend again.