You have probably done yourself a great favour by working out some character background. It is something I recommend to new writers because it helped me so much. The thing you need to remember is who you are writing for with the background. The background is for you, the story is for the reader.
In any given scene you include what is necessary to advance the story. However, the background work that you do will flavour, sometimes very subtly, the things the character will say and do.
If you have done your background work well and truly realised the characters before writing you may be surprised to find that readers are able to work out facts that come very close to the background without every explicitly having been told int he story.
For example, imagine a romance subplot where the protagonist has been through three bitter divorces. Her friend decides to leave her husband for no good reason). Her reaction is not just to prudishly disprove as in your original plot plan. Instead, she is going to act like her friend has done something very self-destructive, maybe even hosting an intervention.
There will almost certainly be a moment where she says something like "you have no idea how bad it can get." Thus, implying personal experience. That personal experience was something you discovered during background and is part of what shaped the character.
99% of the time the background writing is just for you and you will almost always work out a lot more than you need to put in. Tolkien spent his life world building which is why Lord of the Rings seems so rich and real. he left out far, far more than he included. What he included was, for the most part, what was needed for the story.
Just let all that work rest in your mind and you will find that the characters are better realised and the story flows much better as a result. The readers might not know how much background they missed out on but that does not matter - they will know that they enjoyed your work.