Jadie and everyone,
I had this exact same problem a few months ago - not the armpits but a pungent aroma wafting up from down below as you have all so eloquently described

.
Didn't matter how often I washed and deodorised and scented (and I was like a woman obsessed), it made no difference.
I couldn't stand it any longer, so went to our local FP clinic. I'm not sure what the equivalent is in the US and other countries but this service is totally free on the NHS here in the UK, the whole place is staffed by women for women, and you don't need to get referred through your GP, you can just ring up. I find them miles better than the doc's for all things woman including MENO, because let's face it, they are women!
Anyway, she examined me and I told her about the stink and she insisted she couldn't smell anything. I could tell she maybe thought I was being a tad paranoid but she took some swabs for testing and the results came back clear.
Another week went by and I was still humming, so I went back and saw her again. She kind of half rolled her eyes as I walked in, but she was very patient with me and at my request, she did another swab test. It came back showing Vaginal Bacteriosis. She explained this is a perfectly harmless vaginal infection that affects millions of women at any one time. It can be caused by any number of things, even washing too much

... and is easily cured by a five day course of antibiotics. The only way you know you've got it is if you niff a bit. It doesn't itch or anything, it just stinks!!
Did the course, and have been stink free ever since! Fresh as a Daisy! And I'm still 49 years old and I'm still going through peri!
What I'm trying to say here is that smelling down under isn't inevitable just because we're getting older and just because we're menopausal. It could (as it was in my case) be down to a simple, underlying cause that can be easily remedied.
I knew my own smell, and I knew the way I was smelling wasn't right so my advice to anyone who is bothered by this is trust your own instincts, cos no one knows your body better than you. If you think you don't smell right, it might be worth getting checked out for VB.