Helga, as she snuggles with her husband Arnold, believes that they are soulmates destined to meet and eventually marry in all dimensions. It makes sense why she would believe so since she did get the man, they've been happily for seven years with two children (two boys), and she's always been a romantic at heart. With that said she would be surprised to learn that she is wrong because for all her romanticism, she is ignorant to the true nature of soulmates.
Soulmates despite popular belief are not two people who are destined to meet and fall in love, despite a great amount of soulmates doing so. Soulmates are merely people who are destined to meet and become connected to one another by a bond, whether friendship, family, or lovers ultimately depends on the reality in which the souls reside.
There are realities in which Helga and Arnold try to date but ultimately fail. Sometimes it's due to one of them moving away and the long-distance not working. Other times Helga's holds her heart too close or Arnold gives his too freely and the relationship in turn becomes too one-sided to lasts. Other times Arnold is too intimated by the sheer force of Helga's love or even only dates because her everyone expects him too. There are a few rare realities where they get married only to divorce after seeing just how unhappy they've become.
There is even a reality where there is no Arnold but an Amanda. Amanda will still compliment a lonely Helga about her bow and Helga will become her protector after Harold bullies her for football shaped head in pre-school. By the time the gang enters junior high the Protect Amanda Force will be headed by Helga, Phoebe, Rhonda, and Lila after the girl's notice the sheer amount of fan boys Amanda has. Amanda for her part remains oblivious and thinks it sweat that her friends want to spend so much time with her. Her friends are just rather traumatized by Wolfgang leering at Amanda.
There are realities in which Arnold and Helga are only ever friends. In some it's due Arnold being too afraid to hurt Helga in case a date between doesn't work out and Helga not wanting to risk losing Arnold's friendship. In other realities one of them ends up being gay and the other serves as a support system. In a few they only meet because their children have become friends or are dating one another and they quickly friends, who take great delight in swapping stories of the children's antics to said children's horror.
There are even realities where Helga goes from loving Arnold to hating him and in some cases hates herself. In one it's because she's caught on to that fact he's only dating her because everyone expects him too and she starts to hate him, and later herself, for going along with it, such circumstances ultimately lead to a divorce when she sees how unhappy they are. In some realities Helga can't bring herself to accept that Arnold will only ever see her as a friend or in a few realities won't accept his homosexuality. In one reality Arnold discovers her sabotaging one of his dates and he ends up snapping at her, which leads to an argument and Helga accidentally revealing she's been following him and done this before and a freaked out Arnold calling her a creepy stalker.
Perhaps most telling of all are the realities in which the two of them never even met due to their parents making different choices. Some of these choices include Big Bob being practical over ambitious and rising through the ranks of an established company instead of moving to Hillwood and establishing his own, Miles and Stella raising Arnold in San Lorenzo sometimes even living with the green eyed people, or even their parents marring later or earlier than they did in the main timeline.
As if the universe and all creation recognized that something had gone wrongly there have only been three realities with variables that have never been repeated. The first is where Arnold is the bully hiding and running from his feelings, the second where Helga was born a boy, who became so bitter and wrathful that he ended up in a juvie and later jail, and the final and most disturbing of all was an Arnold on par with Aizen with Helga starring as a Hinamori who do not survive.
Helga believes that she and Arnold are soulmates destined to meet and eventually married in all dimensions. Its best that she clings to this belief for the truth would be too much too bare.
Author's Note: I'm not sure where on this came from, just knew it wanted to written and figured I share it.
In case someone is curious Phoebe and Helga are soulmates who always end up as sisters and Arnold and Gerald are soulmates who become brothers. I just couldn't think of a way to establish it in the story without messing up the flow.