My W has told me a couple times over the years that she's noticed the age diff, but I don't think it really matters. She's now involved with someone who's older than me, and she's hanging out with other grad students that are 9 years younger than her. IMHO I think age difference is used as an excuse when there is some other problem that isn't being mentioned/dealt with. Within bounds, of course - some age differences would clearly impact the R.
