william and annette were never your average couple.
they met in the spring of 1983, just a couple of years after the hunter project initially took off and william was well on his way to becoming one of umbrella's greatest assets. though he didn't think much of annette at first, it was her personality that initially drew him in; a very assertive, straightforward, no-nonsense kind of woman that didn't put up with anyone's mistakes. and of course, she was also strikingly beautiful- something he hadn't quite noticed until he really stopped to take a second glance.
although he was technically her superior at this point in time, this hardly stopped william from trying to initiate conversation. his infatuation with annette allowed him to begin discovering facets of his personality/sexuality that he hadn't previously been provided with an opportunity to explore, given that he spent most of his time in complete isolation barring albert. william also spent a great deal of time in late puberty grappling with his perceived homosexuality, as he developed a "crush" on albert, born out of the prolonged periods of time they spent in close proximity to each other throughout the duration of william's developmental years. albert was also, very importantly, william's first and only friend at the time. fascination and curiosity gradually progressed into more elaborate sexual fantasies that initially disgusted william- not because he looks down on homosexuality, but because of the current social stigma surrounding it. being a gay man in the 80's was bad enough, but being a gay man at umbrella in the 80's? william did his best to suppress these desires and refused to confront his attraction to men for a very, very long time in an attempt to preserve his "normalcy."
this, of course, did not stop others from speculating about his sexuality. william is a cis man, and as such he was always taught to live up to certain expectations that of which he never particularly cared to fill out. there are a great deal of aspects about his personality and physical appearance that others, especially other men who worked with him, would deem as "feminine" or not traditionally masculine. this led to workplace rumors about william possibly being gay or a "transvestite." he was not oblivious to this (important to note: even after he was married, these rumors continued though not to any debilitating degree).
annette presented william with an opportunity he had been searching for for quite some time: be normal. of course, growing up sheltered in the 70's meant he didn't know jack shit about things like bisexuality, so william was more than happy to accept his attraction to annette as more "real" and "genuine" than his attraction to albert because this meant, to him, that he was heterosexual and thus "normal" in the eyes of everyone else. it was also exciting to him in the sense that for a very long time, william had simply resigned himself to the idea that a relationship was just never in the cards for him. he accepted at a young age that for the rest of his life, it would most likely just be him & his research with nothing else between them, but annette changed all of that. she would give him everything he never once imagined he'd actually achieve in life: love, family, and happiness (much as he'd like to pretend he was content to dedicate his life to his work, william's always been cripplingly lonely- but more on that later). the two of them struck up a casual workplace relationship. they gradually got to know each other better over the course of time, with william requesting that annette be assigned to him permanently so that they could continue seeing one another in private. the relationship brought out a great deal of william's personality that had remained hidden beneath the surface until now; a gentle, almost kind facet to his personality... if not horribly awkward. though he and annette were never allotted much time to do things like travel together or even spend all that much time with one another outside of work, it was the closest thing he'd ever felt to real love. it introduced a whole different side of him that he wasn't previously aware even existed.
william proposed in 1984, only a year after he and annette became official. they were married by 1985, a shocking development for some considering the william birkin they had all come to familiarize themselves with.
much as they did enjoy one another's company, annette and william's relationship was not given nearly enough time to properly develop. they married, bought a house, and it left them with an overwhelming sense of: "now what?" they'd return to their lives as normal, continuing on with their research without hardly getting any time to themselves. then came the topic of children: something they hadn't previously considered until it was brought up to them by others at their workplace. so when are you two going to have a little one running around? thinking about kids yet, will? it was the next logical step in their relationship, wasn't it? they had hoped, maybe, that having a child together might offer them some form of fulfillment outside of work. sherry birkin was welcomed into the world in 1986, named after a song william had grown fond of in his youth; "sherry" by frankie valli and the four seasons. they loved her. but, as is always the case, william chose to return to his work once more. he found that he couldn't stand to be away from it. it was like an itch, an incessant needling at the back of his mind almost like withdrawal. leaving felt wrong- like he was doing something he shouldn't, something punishable, feelings that were partially exacerbated by untreated mental conditions such as ocd and psychosis.
the truth is, william was never fit to be a father. a husband, maybe- if he and annette were ever allowed an opportunity to truly blossom. but without proper guidance he fails to provide what is necessary for a child in the sense of being present and emotionally available. he is not unlike a child himself at times, as is evident by a great deal of his behavior and lack of emotional maturity and social development. loving sherry did not change the fact that he was a terrible father. it did not change the fact that ultimately, it was his research he "loved" more than her, and annette was left behind to try and pick up the pieces.