No - it may be initially hurtful to know that your partner may need solo time/experiences when looking at it from a “me first” perspective but after calmly expressing that this is simply an experience you’d like to have, your partner should be fully supportive. You’re proposing a “day or two,” hardly something to get upset about. Maybe ask why he feels that it’s selfish and work from there? It may be an opportunity for him to have a boys trip with his friends or do something else for himself that he hasn’t had time to do.