I live in Fairlight and commuted daily to London via Hastings, the train journey is in the order of 1h 40m to Charing Cross. From Rye you would have to get either to Hastings or to Ashford, then from Ashford I would estimate another 1h 40m. Either route would cause you about a six hour commute.
I now drive to Stokenchurch in Buckinghamshire once a week and can confirm that the M25 is as bad as ever. I would expect your husband to endure at least two hours either way.
Rye is a beautiful place, but is not for the daily commuter. Working locally is great but it does not deliver London salaries.
A tough call, but it depends on your need to commute for 30 hours to deliver a 37 hour package of work.
Of course the above timings are all best case! I am not being negative, this is a realistic answer to your question from one who has endured it for many years.