You are not only being a doormat, but you're being a nagging, whiny ninny too! Come on girl, you know what you should be doing. Instead of giving that kid all of your power....get up off your knees of begging and pleading, and start showing some spit and fire!!
Stop going over & over & over it with your H. Do you really think he's going to tell you that he's hot & heavy with this teenager? Why would he do that when you are supporting him, then going home and acting like his nurse maid?
Look, the man is obviously bored and wanted some sparks, so why not show him that? But instead of pursuing him, start dolling up aNd going out at night and getting yourself a life! You are smothering him worse than an old setting hen. Maybe you need to remind him (and yourself) what it was that attracted him to you in the first place.
Instead of acting in fear of what he may do or what that 19 yr old may do......get some spunk and take charge.
Hey, I know women have power......you've just forgotten how to use it. Men say that the sexiest thing about women is self-confidence.....which we can have at any age. The older we get, the more confident we should be in ourselves. I'd say you have a little edge on the kid, wouldn't you? But if you coward down like some defeated animal, then that won't fly. I think you've got what it takes to turn this around.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!