Is part of your "opening up" a fetish of cuckolding? Does watching make you feel like you are still connected to your partner?
If so then you need to either figure out how to let that go and deal with it, or have you wife find another partner willing to do it. The reason I put 0 onus on the bf, is because I don't think he should be forced into something that makes him uncomfortable.
You being able to fuck her in front of him, does not mean he should be able to. Its just not fair.
I think the main problem is the sharing of emotions. I feel as though I am now the thrid wheel and don't receive much if any emotion from my wife, whereas our new friend(I'll call him MD) has been the primary person receiving the most from the relationship(well my wife has been the primary receiver but I hope you catch my drift).
There is no magic way to fix this. I don't believe affection/time/etc are all unlimited. I believe they have their limitations. By opening up you can sometimes feel like you lose some of that to the other person, if the other person isn't careful. NRE is a big challenge as the infatuation stage is powerful and in the hands of the wrong person can create serious neglect.
This has to be fixed in multiple ways.
Your wife has to be made to understand her focus has changed and she is treating you with less.. "love".. discuss it with her, hell give her examples. She may not see it.
and you have to realize being open can create this vacancy for a time and you need to accept you may not get all of the love/gush you once did. There is only so much time in a day haha..
Best of luck.