I think I identify pretty well with the husbands and wife that have been mentioned.
"I don't know" comes out of my mouth a lot when I can not articulate my feelings or am stalling for time to sort them. Or when I just don't want to bother to sort them. I'm working on it.
I tend to say things in my head a million times over before deciding whether or not to force myself to spit it out or not.
I'm getting better about it, but it is a long, slow process for me. It's hard for me to identify certain feelings, and even harder to find the root cause of them. Kind of a learned helplessness left over from childhood.
Someone suggested email. That has certainly helped me to communicate with my boyfriend during this transition. I'm getting better about talking to him face to face, but in the beginning, I just couldn't. Or wouldn't, I guess. It was too uncomfortable and I wanted nothing more than to avoid it.
So, I second email if he can't be convinced to talk about it face to face. I thought my boyfriend seeing other people was a deal breaker, too. Maybe it is and I just haven't realized it yet, but I'm still working on my insecurities with him; sometimes it just has to be through text.