Does aging change ADD?

I believe my ADD is escalating rapidly as I get older.  Is this common?

I have had a mild form of ADD since early childhood.  I always day-dreamed a lot in class.  I had trouble following along with what was going on and what was being asked of me. I often was confused by directions or misunderstood the meaning of what was being said.  I was never a very good student.  I couldn't listen *and* take notes.  I was bad at planning long term projects.  The list goes on.

I was highly functional as an adult.  Held steady jobs, was looked to as an expert in my field.  I could read, work, do tedious tasks for hours on end without difficulty or complaint.  I traveled and used to teach. I never thought I had anything like ADD.  Then my first short marriage failed miserably after 3 years.  I blamed her of course.  However I sought counseling and rebuilt myself and my life.  I went back to being a success in other areas of my life.

6 years later (age 36) I started my second marriage to a brilliant young successful woman. I have never been so blessed in my life.  We were very happy together.  We had two lovely children and had what seemed to be the same typical struggles that couples always have when they first have kids.

Around age 44, my wife and I started having a series of arguments that are absolutely typical for an ADD household.  She would insist she told me something, I would insist she never did.  I was starting to forget things and was in denial over it.  Over and over these arguments happened with increasing frequency.  It was driving us both crazy.  I spoke to my Doctor, she said "Eh, these things happen as you get older.  Don't worry about it".  It was destroying my marriage.  I did research.  My wife did as well.  She suggested ADD (my son had been showing signs of ADHD for years at this point).  So I went to a psychiatrist and got diagnosed.  He said my case was very mild, but since it was driving my marriage down the path to a divorce, I should try medication.  It was *great*.  It was like wearing prescription glasses after squinting all the time to see things.  I was able to think clearer, remember things, keep up with her in a conversation.  It was a life saver.  It didn't last.

After a couple weeks, the dose lost effectiveness.  So we went up a notch.  Worked great for 6 weeks.  Then another raise.  Good for a few months, then another raise. Six months later, again etc.I finally topped out around 40mg/day extended release.  I was at that level for about 4-6 months, then I started having sleeping issues and we had to back off.  We have tried other medications, but eventually just returned to the generic Aderall at 30mg/day, plus a couple boosters.

The problems is, even when fully medicated I am still have issues.  Sometimes I forget small things.  Sometimes it's big things.  I will get confused over instructions, misread emails.  It has taken me months of screwing things up to finally admit things are quickly declining.

To recap - until 5 years ago (age 44) things were going along pretty well.  ADD had no significant impact on my life or marriage.  In the last 5 years, I have gotten so bad that even medicated I am making mistakes and forgetting things on a fairly regular basis.  My marriage is in a shambles and even with full time counseling for both of us we are barely holding it together. Is this sort of rapid decline normal, or should I be looking for some other cause for my deteriorating faculties?

I have had zero luck on the internet finding any correlation to aging and ADD getting worse.