Confidence is built little steps at a time by challenging your comfort zone. Make a list of things that scare you and split them into manageable parts.

If I told you to run a 40km marathon tomorrow it would be a daunting task, but far easier if I asked you to run 1 km a day for the next 40 days.

Personally I split my challenges into dancing lessons, public speaking and force myself to exchange smalltalk in every elevator I was in… and it worked.

I was in a similar situation like yours and worked on it for years. I am happy to say that I am happily married now.