WF,
In my opinion, an affair is not your answer. Why? Well, because you said it yourself.....
I want a husband that cannot wait to come home to his beautiful wife and kids, and make love to her 4 times a week. I am not getting what I need out of this marriage.
You will not get that out of an affair. Two people involved in a relationship that want a future together have to be both emotionally and physically available to pursue that goal. If you are still married, you aren't available.....and if he is married...he isn't available to you....so what would be the point then of the affair?? Does that make sense to you?
If you know or feel that your marriage is over or not giving you what you want and are ready to leave, then why not do it....why not free yourself up and look for that possible relationship that you want to have? Unless you just not ready yet....unless you still have something that is holding you to this relationship....unless it is "him" that you want to be "that" husband......in which case you don't want to add an affair to the list of issues that you both need to work through before you get to that happy relationship you so desire.
But if it's just over and you're just there for some purpose, that only you know why...and you just need the little attention someone else might give you...well, just realize that what you have with an affair relationship is not permanent (for the most part) and is not going to go where you want it to go. It's a "for the now" situation and does not usually have a future...and presents it's own set of problems if you become to emotionally involved and expecting of that other person (who is not available or your not available to). You really need to think about it more indept before taking that step..because you can't take it back.