Is it normal to have wife who wants sex with another men if i allow

I am very happly married for last 7 years, my age is 37 years, and my wife is of 33 years we have two kids and we love each other very very much.she takes so much care of me and is always ready to help me ,she have been my strong support even during my bad phase of life,and always respects me and my parents,she is very beauty full and very very hot in bed,always ready for sex.but she complaints that i am not so active in sex as per her expectations and want me to increase my intrest in sex.so it all started like this,onces she send me her nude photo with face covered on my mobile, when i appreciated and asked her permission to upload it on the internet,she gave me the permission only to share it with my male friend,and insisted to know there opnion about her body and not leting them know the source of the photo to keep her identity secret.
After getting the feed back of my friends through me about her beautiful body, she mailed more photos of her and again asked me to share with my friends to know there comments.but this time i denied and asked her if she would like to have sex with another man if i permit her,and she was so happy and excited that she instantly excepted my offer she said would like to have sex with some one who is familier to her and is comfortable,and more healthy and attractive than me.and said she always fantassies the same.now my question is should i allow and arrange the same and is it normal for wife to have sex with another men if she gets the chance ,will she love me the same and have sexual intrest in me the same even after her sexual experiance with another man.