I am so sorry for your loss.
Navigating the stages of grief is a challenge.
Is it wrong for me to think that this is not a good time for him to start a new relationship? Is it wrong for me to wish he'd at very least put off meeting her a month or so till he could help me work through my grief or is that too much to ask of him? I feel like, if he loved me like he says he does, that he'd be more concerned about me and how hard a time I'm having right now than in starting a new relationship, but I'm afraid they're already in NRE mode and I'm...already being pushed aside and it hurts terribly.
I'm not hearing what you want boyfriend to DO. I just hear this:
I want BF to stop seeing his other GF. (Nothing to do with you, actually. And if he stopped seeing her then what? What's he supposed to do to you/for you after that to aid you? Can't we just skip forward to that part? )
- I want BF to help me work through my grief. I want him to do this by _____?
- I want BF to express concern for me in my mourning time. I want him to do this by ______?
- I am afraid of being replaced. I want boyfriend to reassure me. I want him to do this by ________?
What are the things you need to be comforted? A long heart to heart talk? Listening? A warm blanket? Distraction from your grief by taking you out?
Tell your BF the HOW. Then perhaps he can execute it to meet your want/need at this time.
Don't forget you have a son and husband. They have suffered loss as well -- the loss of a grandparent and FIL. Perhaps helping to comfort THEM would in turn help comfort YOU? Stories shared about him, memories revisited, etc.