First off, these feelings that you are dealing with are perfectly normal. I'm pretty sure almost everyone who is new to poly deals with these things.
Have you ever heard of compersion or read the book "The Ethical Slut" or "Open"? They are really good for helping to deal with these feelings. I look at my jealousy as an opportunity to grow as a person rather than an emotion that cannot be helped. Also, you need to own your jealousy; let your partner know that you are not blaming him for your feelings, you are looking for some support and maybe some suggestions, and you can make some suggestions of your own as well and hopefully have an outcome that's agreeable to everyone.
So instead of wishing you were receiving PDA, how about initiating it? Your DP may just all wrapped up in NRE (New Relationship Energy) and not realising that he's leaving you out of certain things. Be confident! You are the primary partner. You know that DP loves you and wants to marry you and have babies with you. DGF may be new and exciting, but she is that way to you as well, right? She is not replacing you in any way, but adding to your relationship. You are different people and cannot replace each other in any way.
As for baby making and parenting, my situation is different from mine, but I'll let you know what my experience was/is, and you can take from it what you will.
It was hard to get used to my DP parenting my son after being mostly single for six years, and sometimes I wanted to tell her not to. However, I realised that as long as we had the same values about discipline, etc, having her reinforcing what I said and adding things of her own only strengthens all of our relationships. Plus it's really nice having an extra person backing me up!
I also really wanted to get pregnant for the longest time and was going to conceive on my own with a donor, but then DP walked into the picture and also wanted to have babies. She's older than me, so we decided that she will get preggers first. I was a little put off at first since I wanted to become pregnant so badly, but now I realise that with both of us able to be pregnant at different times, our family will only grow with love! I've learned not to be jealous because I still get to have babies too. lol
I really love your advice. I totally agree with practically everything you've said. lol. And best of luck with your "estranged wife" returning to you!!