This is where many men vary in their wishes and/or fantasies. Some men would love to see their wives kissing another man and being intimate, whereas other's would never want their wife kissing someone else. There are reasons for both and varying degrees of feelings on this, however the thought of another man sparking this level of intimacy can be a great source of motivation for a woman to really enjoy the romantic side of things to whatever degree possible.
Assuming a husband would love to see his wife kissing another man, there must be some reason that he would want this. It isn't because he doesn't love his wife, it is mostly based on him seeing her pleased. Often a man feels that his wife would be re-inspired by the excitement of making out with this new man. After all, kissing a new man is something that brings back a certain level of their youth and freedom.