Since the beginning of the show, fans have loved the guessing game that is caused by the unknown identity of The Mother. In Challenge Accepted we find that not only Barney gets married, but also that Ted meets his wife (the eponymous character) on the day of Barney's wedding. In the Season 7 finale, Barney's wife was revealed to be Robin Scherbatsky.
However, it is revealed in Last Forever - Part Two that in 2016, Robin and Barney get divorced.
- In the end of The Exploding Meatball Sub, ten years after the events of the episode Barney is not shown wearing a wedding ring and neither is Robin which indicates that their marriage does not last. Since he has tricked everyone into thinking he is on his death bed for the prank, one would assume his wife should be there. Since the only women present are Robin and Lily, this implies that Robin must be the one. Robin is also seen giving the "Angry Look" described in Robin 101 as she would probably be the most angry if she were his wife.
- Ted is of course Barney's best man. This may also be a reference to False Positive where Robin asks Ted to be the best man at her wedding.
- Lily is the one to get Ted when Barney summons him in Challenge Accepted and again in The Best Man when the bride wanted to see him, somewhat implying that she may be the Maid of Honor, which she would be the logical choice if this was Robin's wedding.
- In The Best Man, Lily realizes Robin still has feelings for Barney when she uses her truth voice (where she is trying to pass something off as a lie when it's actually the truth) saying "I wish Barney were my boyfriend again."
- In Ducky Tie, Victoria told Ted that all his relationships have failed because Robin is a bigger part of his life than he realizes and that the three of them (Ted, Barney and Robin) hanging out, just as friends, doesn't work. Future Ted reveals that she had been right. He just didn't know it at the time Victoria told him. But since Robin is said to be Aunt Robin in many episodes, they must still be good friends. If that's the case, then what Ted implies is that none of his relationships work until Robin gets married, possibly to Barney where Ted's relationship to the mother begins.
- In Tick Tick Tick, Barney admits he wants to get back together with Robin after they sleep together. Barney confesses to Nora that it did mean something to him. He puts rose petals on her bed which he then takes off when he realizes that she didn't tell Kevin. He is truly hurt by this so much so that Future Ted says that the next second after finding out lasted a thousand years.
- In Symphony of Illumination, Robin says the father of her imaginary children is Barney. But this could just be another part of her imagination.
- After Ted comforts Barney about choosing the right tie at his wedding, Lily comes in to tell Ted the bride wants to see him. This means Barney's wife is familiar and comfortable with Ted, and the only girlfriend of Barney (so far) who is close to Ted is Robin.
- In Last Cigarette Ever, it is revealed that Robin's last cigarette is in June 2013, which is likely to coincide with the date of Barney's wedding.
- In The Magician's Code - Part Two, Robin is revealed to be Barney's bride.
- Barney and Robin get engaged in The Final Page - Part Two.
- Season 9 is mostly focused around Barney and Robin's wedding. They finally get married in The End of the Aisle.
- In Last Forever - Part Two, it is revealed that in 2016 Robin and Barney get divorced.
- Becki Newton has joined the show to play Barney's next love interest, Quinn. She will apparently be able to match Barney. The writers have said "Becki's character is going to be a spitfire, someone who can give it back to Barney and leave him speechless. It's a little Frasier Crane and Lilith Sternin — two people who've met their match. He needs to lock horns with somebody to get his mind off what's happening." 
- In Karma, Barney tries to get Quinn to go on another date with him, when he finds out that she works at the Lusty Leopard. She takes advantage of him at first, but they end up having coffee together, at the end of the episode.
- In The Broath, Barney and Quinn decide to move in together. Barney has never taken this step with any of his other girlfriends.
- In The Broath, Barney asks Quinn what would she do to give up her job as a stripper and she replies getting married.
- In The Broath, Barney and Quinn are described by Marshall as being "perfect for each other".
- In The Broath, Ted says "and that's how we met Quinn." This may mean that Ted's children know Quinn.
- In Trilogy Time, Barney tells Quinn that he plans on being with her for a long time.
- In The Magician's Code - Part Two, Barney proposes to Quinn. In the end, however, Robin is revealed to be Barney's bride, which means that Quinn and Barney will break up later on.
- In The Pre-Nup, Barney and Quinn don't trust each other so they break up.
- Nora is Barney's third serious girlfriend, after Shannon and Robin.
- They meet on the day before Valentine's Day at MacLaren's, when Robin invites her female co-workers to protest against Valentine's Day. Barney flirts with Nora, but she understands he's just trying to get in to her pants and rejects him. Barney comes back later and apologizes, and they wind up discussing Laser Tag the entire night. As Robin and Barney made plans to play Laser Tag the day after, Robin sees how smitten Barney is with Nora and sends Nora instead of her. According to Future Ted, that's how Barney for the first time ends up on a date on Valentine's Day. (Desperation Day).
- As Barney is how he is, he denies the fact that he has feelings for her. At last, he decides to call her and ask her out on a date, and this is practically his first time ever doing so. (Garbage Island)
- On their second date, Nora tells him that she wants to get married and have children, and he responds that that's exactly what he wants too, making it possible that she could be the bride at his wedding.
- Although they didn't work out the first time because Barney kept lying to her (A Change of Heart), she is shown just before we find out that Ted meets the mother at Barney's wedding.
- Barney meets Nora again in Challenge Accepted, and asks her out for coffee. She was a strong candidate as she was the first woman he seemed to really care about after Robin.
- He has waited two months to sleep with Nora, longer than he has waited with any woman, proving that the relationship is serious. (Noretta)
- In Tick Tick Tick, Barney and Nora break up after Barney tells her he cheated on her with Robin.