Originally Posted by YGirl
I didn't mean to come across as though I think the OP's have trust issues (although they might)...
OK, then I will come across that way - you have trust issues. Period.
Because that is, in my opinion, the key to all of this. A good, solid relationship is built on mutual trust. It sounds like he doesn't trust her because he suspects that instead of expressing what she feels, she is trying to control him. The subtext seems to be here that this comes from experiences in a previous relationship rather than due to something with this one.
Conversely, because he cheated on her, she has trust issues around whether or not he is going to be able to even keep his promises in the future.
So anything that is said is going to be received with this "filter" in place on both parts. This, to me, is the core of what the two of you need to work on - you absolutely 100% need to get yourself into a position that you can trust each other to do what you say and say what you do. Without this all the rest is window-dressing.
If you don't feel capable of working through these issues between the two of you, then I would strongly suggest some professional help.
Trust is the foundation of any relationship, poly or mono. Without it, all of the relationship is going to founder at the least sign of trouble. That's not what either of you need, I assume.
As for existing "relationships" with others, ask yourself what is important - having these new relationships or working on your existing one that you are committed to. If #2 and #3 respect your relationship with #1 then they will also be prepared to give you some space to work things through and to try to establish that foundation without distractions. If they don't respect you relationship with #1 then ask yourself whether they are really people you want in your life, if they don't understand how important #1 is to you.