I did this (actually, retired for another reason, but the 2 largely co-incided) and we hve decent pensions.
It's an 80 mile round trip - the 40 miles there takes about an hour (but see below)
I began this 10 years ago, and for the last 9 we have done it as a couple. That began because we all wanted to do that, but for about the last 4 years it has been a necessity as my arthritis won't permit quick physical reactions.
The youngest GC is now 3.
I take it that the drive is 70 miles each way, which is quite a lot, so you need to consider that (and traffic). With that journey I would think:
Do you want to stay over? 2 nights eat into your week, but can be very pleasant for everyone. We sometimes take then opportinity to visit friends who live about halfway.
If you are driving in the morning, what is the back-up plan if you get held up? We allow an extra half-hour, but have occasionally been caught badly.
What are the general relationships like and how much do you get together anyway? I'm very glad that we have a relationship that doesn't rely on hard-pressed parents finding time at weekends.