User eXperience (UX) is becoming increasingly important for success of software products. Yet, many companies still face various challenges in their work with UX. Part of these challenges relate to inadequate knowledge and awareness of UX and that current UX models are commonly not practical nor well integrated into existing Software Engineering (SE) models and concepts. Therefore, we present a conceptual UX-aware model of requirements for software development practitioners. This layered model shows the interrelation between UX and functional and quality requirements. The model is developed based on current models of UX and software quality characteristics. Through the model we highlight the main differences between various requirement types in particular essentially subjective and accidentally subjective quality requirements. We also present the result of an initial validation of the model through interviews with 12 practitioners and researchers. Our results show that the model can raise practitioners' knowledge and awareness of UX in particular in relation to requirement and testing activities. It can also facilitate UX-related communication among stakeholders with different backgrounds.