In the article reasons behind searching for life partners, the most important values/factors deciding of the other sex attractiveness, ways of behaviour of partners remaining in a close interpersonal relationship, preferred strategies of behaviour in conflict situation as well as reasons of interpersonal relationships breakdown were reported. Women more often than men mentioned easing the feeling of loneliness as a reason for beginning interpersonal relationships, whereas men more often listed maximising pleasures and minimising dissatisfaction. Both sexes considered personal traits of a life partner as very important. Assessing attractiveness of the partner, men’s attention was attracted by appearance and beauty of women, whereas social and material status of men was more important to women. The main reasons for misunderstanding and breakdown of relationships was an attempt to impose own will and character differences. Both people creating relationships and long term couples may benefit from the results of these studies.