I've been married for almost three decades.
First - if it's hormonal - then you're kind of screwed, but it shouldn't be hormonal if she's around the same age (early 30's) as you are. If it's hormones - she'll need to see an endo about them, and you'll have to convince her to go see one - or something else will have to happen that convinces her she needs to see one.
I don't think it's hormonal though (most women know when their libido has fallen off and they want to know why). Here's the thing ... women don't have to erect a rocket each time they want to have sex - they just have to show up with a good enough attitude to get through 40 minutes or so. They don't need a drug ... they just need to be receptive and have a bottle of K-Y perhaps. So, what you find, is that even women with a lack of libido will make sure they "present" themselves often enough to their man to keep him satisfied. That is, if they view the relationship favorably and the man favorably.
Even if they have no libido though - the woman will often "get into" the act after the man begins his rituals on her. I know I'm not the only guy who's heard this from women. You all have. "I really wasn't into having sex tonight - but then you started kissing me and ... "
That's the way it works a lot of the time with them.
Soooo - even if your wife's hormones are screwed - there's still something in her that's causing her to neglect the sexual relationship. That's intentional - because, as I said - sex isn't "hard" for women, especially two times a week. A woman with a castrated libido can FAKE her way through twice a week standing on her head.
What's causing her to lose concern for the sex?
Is she cheating? Because women who are cheating will attempt to limit sex with their hubby's to the absolute minimum.
Is she overworked and stressed? Is she a Mom? Working, cleaning, and doing everything for the kiddies?
Is she mad at you and playing passive / aggressive with her most potent weapon?
You need to sit her down and talk about this and figure out what it is.
Don't try any **** with her like "ignoring" her. Been there and done that. It doesn't work. In fact, word of advice - you will lose in any passive / aggressive pissing contest with a woman - they play on a level far above us. Best thing to do is sit her down and talk to her.
If that doesn't work - then you have to make a decision to stay or get the hell out. You'll get it once a week - or you'll have to step out.
One thing I will tell you is that Mrs. Honda suffered a temporary case of this many years back - she was overworked and I was absorbed in a very important job. I got involved with another woman and she caught me (in the gym with her! LOL) ... Mrs. Honda's reaction though - wasn't to yell or get upset. No, she turned into the sex kitten I had always known - and broke out the whole sexual buffet and, quite frankly - when Mrs. Honda's game is on she can fry any other bitch out there. I remember, one day after we finished with sex - she looked at me and winked and said ... "She's not as good as me - no way!"
She was right - and that ended my trist with the other girl. Now, mind you - Mrs. Honda told me many years ago that straying was okay as long as it was for mindless sex and it wasn't in her face. It also had to be 100 percent safe sex because she didn't want to catch anything. She knows I like variety and so the rule was not to get involved with anyone I could fall in love with. But this girl I was involved with in this instance violated that rule - because I had an ongoing relationship with her. She wasn't someone I met in a pub and did one night on a business trip to London - which is okay per Mrs. Honda.