I absolutely agree with sara.
You can't have your cake and eat it - it's not fair on the cake(s) to be divided up into such sections.
You will get over 'the love of your life', but then again, you will get over your wife. What you may never get over is the hurt you will undoubtedly cause - but that, I am afraid, is a fact of life.
Make a decision as to who you really want, and stick to it.
You may find though, that in time your wife will make that decision for you. It's no fun knowing you're only second best.