Dividends and passive income is overrated. You would only really be interested in them in retirement, or for some reason your expenses is higher than your working income which is a bad situation to be in. As long as your expenses is lower than your working income, you have absolutely no need for passive income.
Secondly, if you have "really not enough money", then investing is not going to fix your problem. You need savings in order to invest. To fix this problem you need to increase your income or reduce your expenses.
I understand you probably have an agreement with your fiancée to put aside a fixed sum of money each month into the joint account to set aside for your wedding and housing plans. This is a nice idea but one problem is that money sitting in a bank joint account is not earning a lot of interest, and that would be a slight drag on your finances. Investing out of a joint account can be quite tricky as well. See if you can work something out with her to have an agreement to put a certain sum of money every 3 months into SSBs instead using your own individual CDP accounts.
IMO the fast and easy way to get started with savings is to create a DBS Multiplier account. Get your salary credited into a DBS account, get a DBS/POSB credit card and make at least one spending per month on it (easiest way is to charge your mobile phone bill to that), and set up a minimum $100/month POSB InvestSaver RSP into Nikko AM STI ETF. Move most of your money into the DBS Multiplier account. This will immediately set you up with 2% interest credited monthly. Once this stabilizes, then you can come back in here and look into intermediate forms of investing.