Welcome to Pherotalk.
Yes, there are a lot of very disreputable phero sellers out there but you will soon find who the good firms are in discussion here. although this is primarilly ADs forum, discussion of reputable competitors is allowed. 
Yes, they are not cheap but if you do the basic legwork to determine your best doses, they will be cost effective and ADs DHL service to the UK is not cheap but far better than almost any other phero seller (UK, EU or US) that I’ve used that often take weeks to deliver.
As for pheros to help with your wife - there are two broad approaches that can help here:
Socials like IH, can help if communication has stalled, the betanol in IH helps promote reconnection and bonding - Steer that with the happy/feelgood aura of IS to make yourself good to be around. Status products like the very mature A314 or the younger/lighter IG can also help remind her what she first saw in you.
If communication/trust/closeness is not an issue, the sexuals will help sitmualte desire and enhance sex. Ammo - is the all round sexy/social guy and usable just about anywhere. TUTH is mainly designed for use in an established sexual relationship and best kept for when you are getting raunchy. Then there are more extreme products like IJ which can be great fun and personally I find a TUTH/A314 combo works very well around women in their mid 30s and over who appreciate an unashamedly sexual/masculine vibe. Younger/less none tolerant ones can run a mile though.
As for dose, it is more than just using too much or too little but yes, less is very often more - Mone use is all about finding the dose that complements your natural mone output, personality and social situations best. Getting it wrong usually means sending a signal that is too soft/just friendly at one extreme or like walking about with your cock-out at the other. It takes a bit of effort to find whats best.
Saying that, our none output falls as we age, so at 50, you will probably need to use more none than a younger guy and for sexuals, yo ushould consider the 2x ot “Heavy” products from the off - Equally, as a woman ages, her sensitivity to none decreases and she tends to become more used to a much more sexually overt signature.
Which is good because it means guys our age can uuse none in quantities and combinations that would be very difficult for a younger guy! 
This thread covers all the basics of mone use and finding your best doses:
Learn it well!