That's fine. Now, try that with 3 kids between 2 and 7 yo and fourth on the way. I am not complaining, but running and exercising can become very tiresome, especially if both parents are former high level runners, and want to be more than just "active". Running 80-120 miles per week could be done with one, maybe two kids, if your spouse is just content with 30-60mins of running per day, without racing goals. If you have more kids, you have to scale down, otherwise you will be constantly grumpy, tired, frustrated of not being able to fit in your planned workouts, etc. Regularly running - yes, if you are an early riser and motivated person. Racing and having performance goals? Forget it, with two or more kids and if running is not your (primary) job.
That was a good remark about Peter Pan mode and living for your next half marathon, as somebody else had posted.
Stay active, have some modest goals, but once you have family, there are much more important things in life than hitting 100miles in a week, or dipping under 66mins in local 1/2M. Just let it go, you had your chance for achieving glory, and it is not worth to compensate for lack of enthusiasm in younger years, or lack of talent.