There are a few ways, none of which is perfect or efficient.
First, do a few good old fashioned Google/Bing/Yahoo searches. IF the website makes member's email addresses public (not likely) it should turn up.
Another way is to create accounts at some of the big dating sites and see if you can search for people by email address.
Yet another way is to try a site like spokeo.com - which MIGHT find more than regular Google/yahoo/Bing searches - although you'll have to pay to find out. There may be similar free search sites.
The real problem is that if someone is trying to hide from you that they are using dating/chat sites, if they have half a brain, they arent going to use their 'real' email address. It takes 30 seconds to create a free, throwaway email address at Google, Hotmail, etc - so there is always the chance they are using an unknown (to you) email address.
good advice listed on here. It's just such a shame that any one would use those sites, married or not married. /: My husband was using them and other horrible things from a few years before he met me and he continued to use them until i set up a youtube account with his gmail and he didnt notice it, so I go on there and check the history. It's horrific to me, but i give him a chance to come clean by asking him about it first... He TRIED TO DENY IT of coursee.. but I had the proof to show him that I know what he was doing.
The saddest part about your other half cheating online is that you feel you have to become a spy just to get answers to your pain because they thought you weren't that smart. Honestly the best way to catch them is in a slip up, and if you have to be sneaky and set secret restrictions or go on their email when they are asleep then so be it because no one deserves the pains online cheating brings. (cheating is not just physical, but mental..and mentally when they are online doing such things they aren't with us, they are with this other person they are chatting with or watching 'dance' for them being very physical mentally. More then they probably are with us.)
All you have to do is out smart your guilty, mistake making spouse and really just listen and pay attention, without accusing, especially without evidence (The devil is the accuser so we shouldn't really be accusing either) When I'm searching up my husband and going through his emails I get a rush from it. One thing to remember is don't be fooling around because you think they are fooling around. You may be serious and join one of those dating sites to search up your spouse on there, but instead you are the one caught in a spiral, you think your other is on this website and it turns out they aren't.. then you were the one on the dating site. Could look bad. My best advice is be a little sneaky, not foolish, and your cheating spouse will reveal his own mistakes (or that's what is will look like (; ) anyway I've had a hard time and lots of bad anxiety over issues like this, even when they get caught you can not be absolutely sure they aren't getting smarter instead of sorrier like they should. Don't give away your sneaky tactics, act like a dumb blonde about that. So don't tell them how you got the evidence, but that you have it and you have your ways. Otherwise they will just learn more and more ways to avoid getting caught and they will be tempted to do those things again.
My ultimate answer though for everyone is God. He can help us in our marriages. <3 Let Him be the connection between our hearts. Jesus doesn't want heartache. Thank you to anyone who read this.
It's hard to say without seeing exactly what is in them, but they are likely just spam.. and if that's the case, these fly-by-night/out of country outfits generally dont have a 'remove me' option. I get ones like this all the time and I've never used any kind of dating or hookup site..
To locate the source, you have to look at the email 'headers' in the raw-source of the email message. That will only tell you what server the email came from and it's general location (which may not help at all). In reality, you will probably never be able to make them stop unless you change your email OR unless you find that they really are coming from a legit dating site, and they have an option/way to remove yourself.
More information about text formats