The choices you make have consequences. For example, if you choose to work, go to school and have a family, you may have very little left to invest in a sexual relationship. Change your behavior and decisions if you want different consequences. Try delegating responsibility if you’re too exhausted or over-worked for sex.
The quality of a relationship depends on how well it meets the needs of those involved. Consider your partner’s needs as legitimate, and look at how you can meet those needs. Don’t label your partner as being wrong or having something wrong with him/her because that dismisses the issue.