I'm new here, with a puzzle, and hoping I could get some pointers from you all

I'm not really really new to family history, but it's been a while so I'm a bit rusty. Here's what I've come up against (I hope it's clear enough, I'm not known for my clarity).
The information I was given about a lady (A - sorry, I'm a bit more careful about what details I give out online these days, but perhaps I'm being too uptight?) was that she was born in 1914 in or around Aberdeen. She then married in 1936/7 in England, probably around Bournemouth/Poole area. Her husband, R, I have 'fairly' solid information about - birth, death, 1911 census, children, etc. However, I haven't been able to find A's birth around Aberdeen around that time (spanning from about 1900 - 1920), though there are other people born in that window with A's surname in other parts of Scotland.
(Another complicating factor is that I've got a couple of different alternative sets of first and middle names for A. Yeahhh!

Neither could I find any trace of a marriage between A and R around 1937. What I have found is that R married S in 1929. S seems to have been born in 1904, not in Scotland, but in the same county as R. I can't find any death record for S, either under her maiden name or R's surname.
Sooooo I think I have two possibilities. Either A and S are the same person - in which case I suspect S took on a new name, history and so on (A's birthdate would make her 14 or 15 in 1929, which is when R and S married - but maybe with a bit of fibbing and a lenient registrar/vicar that was doable?). My question then becomes, like, WHY

Or A and S are two different people. I can't find any other marriage record for R, and from his info he didn't seem the kind of guy to fib about his name (though what people get up to in their youth, ahem ahem, you never know), so he and A would have been common-law, I suppose? I can't find S' death though, as I said; she could have remarried and have died under a different surname altogether.
Did R and S divorce? R wasn't from a wealthy family, so I'm not sure if he'd have been able to pay for it. Did they go their own ways and did R, ahem, meet up with A later?
That's the situation with some of my questions mixed in. Here's the information I either have, or am ordering:
- R's entry in the 1911 census - on comp
- S' entry in the 1911 census - on comp
- R's birth certificate (ordered)
- R and S' marriage certificate (ordered)
- The birth certificate of a child of R and A (copy being sent)
- R's death certificate
- A's death certificate
Do you folks have any tips for me?