I am new so bear with me...I need some advice

[my_rollercoaster_ride]

Hello. I am new here and am in need of some advice from anyone right now. I am not sure if this is the correct forum to post, so let me know if it isnt. I am posting in the sex starved marriage forum since this has everthing to do with that. I thought about the midlife crisis forum since I am pretty sure that my husband is going through that as well. I dont quite understand all the abbreviations so I will just spell it out. This is hard for me to even write about since I do tend to be a private person, but that is not helping me. I can and will go into more details about my husbands midlife thing, but this question I have is about sex. I am not sure if the MLC plays into this or not. We are in couples therapy right now and have not had an opportunity to talk about this yet.
My husband and I have been married for almost 6, together for 9 and known each other for 12. When we were dating prior to marriage the sex was CRAZY! I guess lustful is the word. It was great. And it still is even inspite of othe issues. It is just very infrequent now. I have a very high sex drive. At one point so did my husband. In the last 2 years it has gone downhill. I still want this and my husband is, well less than interested. Long story short, we started counseling a few weeks ago and sex has definately been more frequent. But during our "communication" exercize that we do every evening my husband started talking about us having sex with other people. Not affairs, just sex. He said he would like to watch me do this with another person and even participate and he would like to do the same thing. That he found that exciting. I realize that there are "open marriages" and that people do these things, but is it normal especially when a marriage is already trying to be worked on? I am 40 and my husband is 38. I guess what I am asking is this a normal thing for a man to want? I am trying so hard to work this out in my mind, I guess I just need someones opinion. Please.