This is the first part of a project dealing with both a formation process of pair bonding between adults and some disadvantageous factors affecting the bonds. The literature review on pair bonding is presented. Four factors constituting pair bonding are discussed: (1) the number of sexual partners, (2) whether or not one was subject to sexual abuse, (3) exposition to pornography, (4) the age at which one became sexually active. In the research part, subjective assessment of the quality of sexual life and the influence of the four above-mentioned factors on this assessed quality are studied. Major findings include: (1) the stronger was the experience of sexual abuse, the worse is the assessed quality of the current pair bond, (2) the more painful experienced sexual abuse, the greater number of sexual partners one has had, the more one has been exposed to pornography and the earlier one became sexually active.