You say words are not enough, well maybe not but surely they are better than nothing? It's a start is it not? Every marriage goes through a rough patch, it's up to you whether or not yours survives the storm. The greatest killer of all relationships is silence. You might think it is too late, well then you have nothing to lose. Do you want to carry on like this? Any change is better than none at the moment, surely?
You are trying to get inside your wife's head, anticipating what she is thinking, but you cannot do that. Only she knows how she feels. You cannot tell what her reaction would be if she read this thread, she might be annoyed, or astounded or saddened. In any case you simply have to make your feelings known to her, she is no more of a mind-reader than you are. She might think that you don't mind things the way they are, she might think that you are no longer interested in her, she might think that you are having an affair yourself. One thing is clear on this thread and that is how much you love her. So whatever way she chooses to read what you have said, she cannot deny that much. Your love for her rings out true and clear. At least if you show her this thread, the ball is then in her court. It is up to her how to use the knowledge you have given her.
It will probably be a rough ride for you both. If she is suffering from depression and low self-esteem, it could take her a while to open up to you, she might be afraid of laying her feelings bare, but if you start the ball rolling it may encourage her to do that. She could be waiting for you to make the first move.
I agree, words are not enough, they need to be followed by actions. If she reads this, then make sure you book a nice meal for you both afterwards so you can sit down and discuss it, decide what you want to do next. She might ask for a bit of space, if so you must respect that and give her all the room she needs. It worked for FatBoySlim, whatever his name is. But if you do nothing, then the situation can only get worse and she may think that you don't care. Be brave. If the relationship does dissolve, then it would have happened anyway. But you need to fight to keep it, and she will respect you more if you do fight for her.