Is it correct to say “at the expense of your own selfish reasons? And what does it mean?

Yes, it is correct to say “at the expense of your own selfish reasons.” This phrase generally means that someone is sacrificing or compromising something—often their own values, beliefs, or well-being—in order to accommodate their selfish motivations or desires. In this context, "at the expense of" implies that there is a cost involved; it suggests that prioritizing one's own selfish reasons may lead to negative consequences for oneself or for others. Essentially, it highlights the idea that the pursuit of self-interest may come with drawbacks or sacrifices.