Interesting, that not one of these other posters has mentioned her perspective. Since Hanko noticed she was looser, isn't also possible that she has noticed a difference as well?
I also noted that all of the other posters also advised against saying anything about her being looser. Well, maybe she is afraid to bring it up for the very same reason; she wants to maintain the relationship. It is also possible that he priority is not how loose he feels, but rather, staying together.
These issues DO come up in marriages. And it is unwise not to develop good and caring communication. A lack of communication can also destroy a marriage. On the other hand, just telling your wife that she is "loose" would be the wrong thing to say. But saying nothing is insuring that nothing will change.
There are a lot of different ways to discuss the subject without risking the relationship, especially if you are creative and express deep affection for her and a desire to share your feelings with her.
It doesn't have to be a conversation about "how loose she has become", but about how your sexual relationship has evolved/changed in the time you've been together. It could be a trip down memory lane and how you would like to see the relationship develop in the future.
The important thing to do here is to make it clear to her that you want to reawaken some of the original feelings you had in the beginning while exploring new territory.
In order for your sex to remain healthy, it needs to be communicative on all levels.
Let me know if this is helpful.