Welcome, PureSoul
I'm in a similar situation, because of my background, having not being able to have the opportunities to develop myself as a person fully because I was practically a prisoner at home all the way up until I finished my undergraduate during the time which I did push a little bit, very small steps (pushed to go out like twice a year. I did start lying during my final year about having to stay late for experiments (up to 11pm -but could only do that rarely such as three times), even those times dad would get agitated, it was like walking on eggshells with him. Being a girl it was worse than how my brother was treated/given the opportunities. There was so much tension with my family and no breathing room. I became a hermit in my room for most of the time.
Only got my full independence about a year ago, but I couldn't make friends because of my confidence and work issues. I didn't know how to make friends. Understanding that everybody is nervous to a degree or another to talk to a new person, and thinking of it as 'wouldn't I like it if someone smiled at me, or small talked in a friendly way at a queue maybe?' or if I was the cashier at some place It'd make my day a little better if someone asked something simple as a sympathetic 'busy day?' with a smile. Talking to someone on the bus, at a cafe etc. So I may not have friends (I do now, all from the Ex-Muslim community group and in a different town lol) but I can be a friendly person/enjoy the simply company of strangers sometimes.
And in all other areas I never developed the strong confidence (e.g looks, intelligence etc), one thing I did have was some work confidence because I was good at what I did, after immensely stressing out over things even lost that over time and had to just somehow get myself together and fake it really. Stumbling along. You do have to fake it and keep it together, not being too introspective. At the end of the day you can't control how every other people will view you completely. There are certain things you can try to do, tips from online to show yourself to be more sociable etc, but you're one person. You just have to leave some things on a bit of faith.
As for your relationship bit: If she's a Muslim and knows you're an ex-Muslim and she's ok with it, then that's her choice. If you're happy to be with her as she is, then that is the extent of your choice -don't go making the decision for her -that it's 'better for her', you make your choice and let her make hers. My two cents.
Topic: Need help with Professional life