Here's the thing Polaris, if she dumped you because you are not affectionate / not showing emotions and you want to change, maybe there is hope for you as a couple!
As a woman I will say it's very attractive for a man to take a risk and show me he cares for me. However, there is a balance. Too much affection too soon can be overwhelming, and relationships that work best are between people that have similar preferences with this. (Not everyone is cut out for constant displays of affection or feelings talk!) Good on you for taking a look at this! I second the Brene Brown thing, I've learned a lot from her books.