I'm in almost an identical situation.
I'm 48, and the last decade has been mostly sex-free. Having a bawling child, and the stress of redundancy certainly contributed to everything going downhill, but performance went in the same direction. That becomes something you don't want to repeat too often, and the "easy" way out is to ignore sex.
Unfortunately, that pretty much triggers a gradual decline in the whole relationship, and in hindsight can't be recommended.
It took me ages to get the gumption to talk to the doctor. I'm overweight, and knew the Doc would want me losing weight, so I only felt comfortable talking about ED once I had got weight loss started.
The first clue I had about this being a testosterone problem was when the Doc asked me to repeat the blood tests, but specifically at 9AM (and the receptionist wasn't willing to book me in at 9:10, so it took a month to repeat!). This gave me fodder to search online, and find the varying advice.
I was staggered at how many symptoms I was showing for low testosterone, but it is hard to get anyone to take basic tiredness, fatigue and a lack of oomph as anything serious. My first reading was 5.6 nmol/L.
Right now I'm about 10 months into the gel treatment, and it took over 6 months to get the dose right (don't get blood taken from skin that you rub the gel over!). I take 1.5 sachets per day, and we're targetting around 20nmol blood levels. A single sachet wasn't enough to properly restore morning wood - which is a symptom I hadn't really notice as it disappeared.
The testosterone isn't enough to fully fix my ED problems, even at a higher dose. At the moment, Cialis adds the final kick, and gives an erection better than I had as a teenager (was my testosterone low all that time too?). I'm not sure either has kicked my libido into top gear yet, but that is a much harder symptom to measure.
So the plumbing is getting fixed, but fixing the relationship is so *much* harder.
After a decade of mistreatment, the relationship needs to rebuild more than just the mechanics of sex, but also the elements of intimacy, touch and trust. These take time, even if things went swimmingly, but previous fractures mean that things don't go in a straight line.
We've found that talking works best. Talking delicate, intimate stuff that we would never have mentioned before. Right now, we're (temporarily) a long distance apart, so we talk at long length on the phone, about what works and doesn't, what we want and don't want. What built things up when we get together at the weekend, and what didn't work so well, or actively broke.
Of course our child, now a teenager, is still a hurdle - very much at the "Ewwww" stage when her parents even appear to be making eyes at each other!
So, I agree with the "take it slow, and re-discover" advice, but make sure you add a lot of talk about the situation.
Lovehoney has been a great help. Both in terms of supplying toys, lingerie and "stuff", but also in terms of inspiration. We can both look at the website while on the phone, and talk about products, pictures and reviews. What turns us on (or not), what is comfortable or beyond. Plus talking about posts we see on the forum. It all helps fuel the conversation.
If things are tough, then you might like some more reading material to help things along. I've found two books useful:
"The Sex Diaries" by Bettina Arndt, (first chapter here: http://www.moresexdaily.com/guest_sexperts/bettina-arndts-sex-diaries/ ), and
"The Sex-Starved Marriage" by Michele Weiner Davis