I will preface this with the fact that I haven't done a single non prescription drug ever and even those I have never abused. I have been prescribed percocet and hydrocodone but usually end up throwing it out after I get better because they give me too much. The most I have gotten out of those is a very light warm and floating feeling but mild. So yeah this isn't quite my realm. Okay I did leave about 6 or 7 pills on a doorstep once.
That being said I have always wanted to try ecstasy. I guess it just goes by molly now? Not sure. I want to try it with the wife for sex. Just one of those things I have always wanted to do based on descriptions I have heard and also the made up crap I see on TV/movies. Is that just the worst idea ever? I have read many a horror story about not enough water etc. I also am not the drug buying kind of guy so how does one even go about looking into that?
I never found sex on MDMA that great - in fact I generally found it a profoundly non-sexual experience, and turned down easy sex several times on the drug just because I wasn't in the mood (though that was in a club/rave context - it's different with a girl, although even then we'd spend as much time just talking or fooling around as actually fucking). A lot of guys have trouble getting it up once it kicks in too. But it is an intense emotional bonding experience, it really opens you up and connects you to people, which can be a great experience in the context of a relationship (which was one of it's original uses - marriage counseling). But it's really not the "fuck like rabbits" drug it's portrayed as. It's also seriously disinhibiting, which can be a good thing or a bad thing, but you really wanna be prepared for when you open up and start saying and doing things you never would sober.
As for whether it's worth it, only you can answer that. The risks are definitely played up a lot, and if you're careful you can make them more or less negligible - but on the flip side, I think if you've made it this far in life without using drugs, why add that extra layer of complications to your life?
So I guess, if it's just a "yeah it'd be interesting" thing then I'd honestly say don't bother. If you and your wife really have a burning desire to try the drug and are gonna do it anyway, then you can minimize the risks if you read the harm reduction literature available.
Maybe read some of the trip reports on erowid and bluelight to get a perspective on what the experience is like:
Erowid Experience Vaults: MDMA (also Ecstasy, E, X, Molly, Adam) Main Index
If you are determined to do it, go with the darknet (you're in Germany yeah? should be able to order some great stuff from the Netherlands without too much trouble). I'm not sure which markets are the big ones right now, but I'm sure you can find out on reddit or wherever. Your chance of finding decent MDMA in-person going in blind isn't great, especially since a lot of what's on the market these days is mephedrone/methylone or similar and not actual MDMA. Why risk it?
Darknet is easy to use (once you get the hang of bitcoins, but there are guides out there for that), convenient and high level vendors literally bend over backwards to provide good product and service to their customers because a few bad reviews can trash their income. If you're a regular user it can be a pain with the constant downtime and having to wait for packages to ship, but for once off/occasional use, it's perfect. Completely different to the crap you have to put up with buying drugs in-person even when you know people.
On top of that, you can buy test kits either online or, depending where you live, at head shops, which will confirm the presence of MDMA in the sample - although it won't confirm purity and only tests for a few of the major active cuts. But MDMA customers in particular are really picky about their product, so if you go with an established vendor with tons of sales and good reviews, then confirm with a test kit, your chance of getting anything other than high quality MDMA is minimal.
As for the dangers - the chance of anything acute happening is low as long as you and your wife are both healthy (especially no major psychiatric or cardiovascular problems), you do everything you can to make sure your product is good (trusted vendor, test kits) and you don't consume it in stupid doses.
Cases of people dying from dehydration/hyponatremia are far and away the exception, not the norm, and tend to happen when people either consume insane doses (intentionally or accidentally) and don't take a break from dancing to rehydrate and rest, or freak out and start drinking tons of water because they think they're ODing (this is what happened with Leah Betts in the UK I believe). Just drink when you're thirsty and make sure your water consumption is more or less in-line with your physical activity, and your chance of having problems on that front are small. To be safe, avoid combining it with alcohol, since that will also dehydrate you.
Other deaths are usually massive OD's (idiots downing half g's at a time, or people freaking out trying to get into festival when the drug dogs approach and necking their stash) or pills cut with deadly replacements like PMA (there's been a bout of these in Aus lately, and it's really tragic because if the cops would stop guarding the gates and let promoters test pills on the site, it wouldn't happen).
If you do go ahead with it, I'd also recommend reading around on bluelight/erowid and similar harm reduction sites to get the basics in terms of doseage and what to expect. If you end up ordering pills instead of powder/crystal, make good use of pillreports.