How long has it taken you to feel fully comfortable with your SO?

I have a complicated relationship with relationships, intimacy and vulnerability. It's always stood in the way of falling in love or pursuing a relationship because it's something that feels deeply uncomfortable. For the past couple of years I have been trying to challenge my limits to fully emerse myself in a relationship.

I'm 27 (f) and am in my first real relationship. We have been dating for 5 months, exclusive from pretty much the beginning and official as of a few weeks ago. He's (26) struggling with being vulnerable just like me which makes it difficult for us to admit to certain feelings or express demands, which means that one of us has to bring up the more uncomfortable vulnerability which so far has always been me. We've just started a long distance relationship as I have moved out of the country. Despite feeling very much in love with him I still feel like I can't fully open up which clams me up at times and leaves me frustrated. I wish I could read his mind but mostly I wish that I could be strong and tell him what I feel and tell him when I need more from him. Until then, I don't think that I can feel fully comfortable with him.

Does anyone have any input, advice, hard truths or word of encouragement to give me? All best x