Yes, poor you! It saddens me and makes me angry that adults pull shit on kids and don't get how vulnerable they are and how it effects their entire lives. I totally get where you are coming from with your jealousy and how crazy it can make you feel. But I also don't suggest you throw the baby out with the bath water.
First off; do a tag search for "jealousy" there is a ton of stuff to read on here and you will see it is not only workable, but very common. Secondly, there is nothing but time. If your partner and this woman agree that it is worth keeping their hands off one another and not spending alone time together for you to work some on this for yourself then take them up on that.
I would suggest asking them for 6 months (insert however long you feel good about, this is what I personally would ask for) for you to get used to the idea of them going on a date together. Then work on it.
Spend time all together, spend time with her, spend time writing, meditating, swimming, going to therapy... Whatever it is that makes you feel confident and able to think about the root of this and then start walking through it.
If you need more time, tell them. If you have a breakthrough, tell them. If you are stuck, tell them. If you need to bounce stuff off of someone and have a good cry, tell them. Don't leave them out because this is what will help you all connect. This is what will make you realize one day that its not a big deal and you wish they'd hurry up and plan a really nice date together.
Time my friend. It is your best ally. If you use it and work on yourself. You will benefit, they will benefit and it will be a win win situation. At least for me it has been
(Don't forget to let them talk too. This will be huge for them also and its only fair that they should have their time to address what is going on for them too.)