We're so lucky.
Yeah, it sounds like you're on the right track. I completely understand how your partner felt about the hand-holding. Unfortunately, we live (no matter where you live) in a society that has some pretty serious issues without any relationship deemed unconventional, particularly polyamory. As a swinger, I understand the need for discretion, you never know who is watching and judging: employers, future employers, board members, whatever.
I've had trouble expressing my emotions in the past too, and really, you just have to deal with making yourself vulnerable. Remember, she needs to hear how you're feeling and what you're thinking every step of the way in the relationship, so do it for her and your relationship. She needs to feel like someone that you come to to talk and confide in, not a hindering presence that you have to keep secrets from (though i think you're past this point).
Celebrate her as I do my girlfriend, as someone who is ridiculously great, and secure enough to participate in a polyamourous relationship.
We're very, very lucky people.