Conflicted about possible sequel

So, recently, people that have read my manuscript have said that perhaps I should consider a sequel with the current MC’s POV. Originally, I never even thought of a sequel like that, because the MC dies at the end. And I like that end. But now the thought is in my head of perhaps letting him live and making a sequel out of it. I’m really split now, and really frustrated.
With this being my first book, I thought it would be better to have it be a stand-alone anyways. And, (please correct me if I’m wrong, but is it true that you only get to do a sequel if you sell enough of the first book?) if this book wouldn’t sell very good, I’d hate to change the ending to something other than what I have and never get to continue on with it (basically leaving a cliffhanger). But after giving it a lot of thought, I do see the potential for a sequel (perhaps trilogy) provided that the MC lives.
Any suggestions as to what I should do, how to handle this situation, or really how sequels work? I’m just so frustrated right now, because I had it wrapped up with a bow on top, and now I’m thinking about undoing it all.

 

No matter what your plans are for a possible series, your novel should stand on its own. When you get to the point of pitching the novel to agents, one of your selling points can be that it has the potential to be the first of a series, but don't expect to sell a first novel on the promise that the full story will be completed in a later volume. That's a nonstarter.

But that doesn't mean you can't plan for a series. There are a number of things you can do while working on your first book to allow for a series later on:
1. Plan your mc's character arc for your WIP and the next two books (even if you don't have a clear idea of the plots of them, just a basic idea of your mc's internal arc progresses will do). Your mc should grow in some new and different way in each book of the series, but may also regress in some ways. I'm currently reading C. Hope Clarke's Edisto series, in which her mc, Callie Jean Morgan, is battling latent alcoholism and keeps wavering, but grows stronger with each book. In Bruce Coffin's (is that a great name for a mystery writer or what?!) John Byron series, his hero detective spends Book One shaking off suspicions of his father and wrestling with saving his marriage, and then in Book Two moves on to a possible new relationship now that his divorce has been settled.
2. Identify a few supporting characters and what their arcs will be in the next two books. Going back to Hope Clarke's series, a minor character in Book One who was antagonistic to Callie becomes increasingly supportive in Books Two and Three.
3. Make sure that each story is separate and able to stand on its own, not just Book One. Even Tom Clancy's Jack Ryan series kept each story separate, even though Sum of All Fears, Debt of Honor, and Executive Orders all follow a chronology of one story right after another.

Hope these suggestions help.

 

Or you could always make them a ghost

 

I think it depends on the story you wanna tell. Surely a trilogy would be quite a different story overall compared to the current novel? Do you feel you've told the story you wanted to tell? Do you think your story is complete as it stands, or would it be a better, more complete story as a trilogy? Answering these questions should help you decide whether to let the MC live or die.

Alternatively, leave the book for a while and write another one. The book will always be there. You'll always be its author, As long as it's not published, there's nothing stopping you from making this decision about its ending at a later date, when you've had some distance from it all and can perhaps see things more clearly.

 

Then do a prequel.

Find a way that he didn't really die.
The old serials they showed at movies in the 50s did that week after week.
The stagecoach went off the cliff killing everybody.
Only next week you see the people jumping before it went over.

Let his brother show up and continue the original MC's efforts.