I have to agree with some other posters, I would spend the money between you, but that's how we operate, it's a shared pot, and always has been.
I remember years ago before we were married, and we had very little money, the soon-to-be-present Mrs Hughes was struggling to raise two children and keep her house, while studying for a teaching degree.
I was at work, and my boss, a bit of a racing fan, asked me to pop down to the betting office and put £5 on a horse - he was advised it was a sure thing, because a lot of horses are trained to win a race at long odds which gives the owners the money to feed and train it for another year - and he had an 'inside' tip.
I was writing out the slip, and I heard the odds - 8-1. I realised that would bring him fifty poinds if the horse won, and this was in the early '80's, and to us, that was a fortune! I decided to back it as well, and we duly collected £50 each.
I have no idea what my boss did with his winnings, but I handed mine over to an amazed student (I have never bet on a horse except the National before or since)and told her to treat herself with it.
It actually paid the electric bill, but needs must, and all that.