You fall for him during your weaker time and got the support which you might have required from him. Accept that people and their priority do get changed over the time. His focus has changed. I know it is difficult to digest such naked realities but you do not have other options. Moreover, when you do not have an option to leave him, you have to stay there maintaining your dignity. For that, gracefully bring yourself out of the race with younger colleagues. Stop nagging him on the issue. Try to concentrate on your work and do it with sincerity. This may not be very easy for you but it is very essential for your mental peace. If life has given you good days after a long time then enjoy them by changing your attitude towards such disturbing things.