Will my boyfriend still be able to have children in future because of this incident?

His fertility is fine. I take martial arts and we have accidentally hit guys there hard enough to make them vomit and their fertility is fine. Granted it's lowered for a few days but fine after. His decreased interest may be due to his bruised ego or maybe his bruised manhood. That takes time to heal. If you'd gotten kicked in the breast would you be ready to let him touch it yet? Don't take offense just try talking to him.