I forgot to mention how I can take away the guilt. First I was baptised, so my sins and guilts were taken by Jesus dying on the cross. Second, if I am defeated by sin, Pastor told me once I asked God for forgiveness and decided I will sin no more, God will forgive me right away. The Bible said, " Sexual sin is not an unforgivable sin like blasphemy. " As we all now had experienced the taste of life and death, how God sees us matters the most. No matter how much other people wants to help us, in events human can't help, and at the last breath, only I and God are in fellowship.
For those people who are insensitive, you know they had been sexually immoral, too, They are just lucky not to have STD. Even those who are not sexually immoral, they may be not attractive enough to be tempted, or they had secretly thought of to have immoral sex, too. Besides, everyone's background is different that only God can judge what lead to the immoral sex.
As for exceptions to those who really restrained from not having immoral sex according to God's standard, they have nothing to boost for God's grace and spirit helped them. Now they do not sin do not meant they will not fall on this in future. Besides, they do not have this weakness, they will have other weakness. e.g. love of money, a gossip tongue.