Too many characters
Question: My story started with four main characters (a family) but soon became seven I am worried that there are too many. I don't want my characters to be just waiting for something to do. Each character is important to the end of the story and the new characters are their love interest. Any suggestions?
Answer: By "main character," do you mean a point-of-view character?
If so, there's nothing wrong with having a number of POV characters. You just must recognize that there's a trade-off. The more you have, the less connection the reader will have with any one character in particular. Having many POV characters will shift the reader towards an objective or omniscient perspective, because the reader's perspective will encompass many perspectives.
Sometimes that's okay. Sometimes that's what you want. Some stories are more about what happens to a community than what happens to one person. Some stories relate what happens over generations rather than just one person's lifespan.
You can also have one primary POV character (a "main, main character") and several secondary POV characters, if telling part of the story from their perspectives is important. You don't have to fully develop the inner conflicts of these secondary POV characters.
However, many readers prefer experiencing a story from the point-of-view of one character in particular who they can empathize with. The price you pay for multiple POVs is disappointing these readers.
On the other hand, if by "main character" you mean "major character," one who is seen from the main character's perspective, but not a POV character, that's a different situation. You can have as many of these as you like, provided your word count doesn't swell too far into six-digit territory. You can certainly give major characters arcs without making them POV characters.
So you have a lot of artistic freedom. For a first draft, you just have to trust your own instinct. Get some people to read that draft to see what their response is and if the story is received in the way you intended. Then write a second draft.