Men and women complement each other. Together each person is able to give to the other what the other lacks, producing a harmony which isn't possible in isolation
Brings two people into a communion of persons (sharing together)
Shows commitment, mutual love and respect, and leads to greater intimacy
Gives the possibility of creating new life (contraceptives should not be used)
Can make use of natural periods of infertility to reduce the chances of pregnancy. Sometimes it is more loving to express fondness through non-sexual acts
Other Christian denominations agree with Catholics that sex should be treated with respect and consideration, and intercourse should only take place within marriage
Many people in Britain, including some Christians, view using contraceptives as a responsible way of preventing sexually transmitted diseases and unplanned pregnancies
Because love is so great, so sacred, and so unique, the Church teaches young people to wait until they are married before they start to have sexual relations
Contrasting/non-religious views on adultery: It may break a marriage promise but there may be a reason why, such as if one partner refuses to have sex. Some may not have made a 'life-long' promise. Personal happiness is important even if it may cause harm to someone else. There may be other reasons why the marriage is falling apart e.g. a very unhappy marriage. Maybe the couple made a serious mistake in getting married and have found a more suitable partner
Many people in British society (including some Christians) believe homosexuals should have the same rights as heterosexuals and so should be able to marry