What is the best way to introduce swining into my relationship?
I did read your previous post and considering what you said there, I am answering here.
Might I suggest you first see if you are going to have an relationship before jumping the gun to introduce your spouse to swinging.
A saying we have for new couples is if you have cracks in your relationship, most often than not swinging will turn those cracks in donga's. Swinging is not the answer to fixing a marriage that has problems, it will most probably damage it more.
We had problems in our relationship many many years ago, without going into to much detail here, we sorted our problems out and then we started to look at alternative methods to spice up our sex life. 16 years later, still in the lifestyle, we are as happy as the day we met and love every moment of the lifestyle.
It took two things, though for us to get here:
Firstly, we had to sort out our own issues.
Secondly, my wife has always been very openminded, so very much into the idea of the lifestyle. If your wife is not openminded or open to the idea of fooling around a bit, you are most probably going to cause more harm. And if she is open to the idea, make it all about her without her thinking you just want to get her involved to have carte blanche to play yourself.