So, Ros, be POSITIVE on this one - you now have the details of the daughter too! It is up to you if you want to get her birth cert too or not.
I can only echo Carol's advise about sticking to facts.
And also about names - my grandfather was always, we thought, William Herbert. He married, twice, in as that name. His death in his 80's was registered in that name. Then his widow looked out his birth cert, and found he was registered simply as 'Willie'. Neither my mother, or anyone knew this throughout his life. But it eventually came to light via his brother who had emigrated to America that when they were teenagers both he (Frank) and my grandad (Willie) decided they wanted middle names, so from then onwards called themselves Frank Victor and William Herbert. And that is what they did. No-one (not even their wives) knew of their previous names until then, about 70 years later.
On the marriage, again I agree with Carol. There are lots of marriages even on the free database ist on ancestry for Ernest Gales, and I didnt look at the spouse name for all. The CArdiff one was to a Lily Moss, but your chap could have married anywhere. The free database is also not complete, and it is not practical to look through the marriage indexes qtr by qtr when we have little idea as to the time scale or place of the marriage.
Having said that, we have now established the date of the daughter's birth, so unless there were more siblings that might help with a marriage date.
Hang in there, Ros, you're doing well! Dont get bogged down with red herrings - just go one step at a time!