Are you and your wife really on the same page about not having children?
What will being a better tennis player do for you?
Will you really be more happy at 4.5 than at 4.0?
How quickly after returning to work will your tennis prowess fall off?
Are you getting up now to work out before you go to work so you can concentrate on your tennis in the evening?
Could you benefit more from your ball machine by working more on your weakest ground stroke and volleying - running to return balls hit far away from your initial position?
Could you currently fit in several 20 minute sessions practicing your serve each week?
At 34, and allowing your body to recover from the training an tennis, how many more hours could you really train and play by taking time off, and not start to break down?