yankees99,
Really sorry you are here. A few thoughts and suggestions:
I am ashamed to admit I did think about ending my life.
You can't make good decisions if you're a mental basket case, so do whatever you need to do to get your emotions under control. That means getting enough rest (mild sleep aids may be necessary), eating regularly (force yourself), lots of exercise (you'll be surprised how much this helps your mental state), NO alcohol and possibly prescription anti-anxiety medication (talk to your doctor). This should be your No. 1 objective right now.
Today I served her with divorce papers, she told me she now feels confused and thinks we can work and save our marriage.
This is really good. Most BHs let their WWs eat cake while they to suffer in marital limbo. Giving her a strong consequence for her adulterous behavior actually increases the chances of saving your marriage because it helps her understand that what she has done will also hurt her and it forces her to seriously think about what she wants.
Exposing is something I have been thinking about. I guess she just expects me not to tell anyone.
If you want to save your marriage, you first have to end her affair. There is no more effective way to do this than to expose the affair to everyone that both your WW and the OM care about (spouse, children, parents, siblings, close friends, clergy, employers). In fact, failure to expose generally dooms the marriage, first because it usually means the affair continues and secondly because it makes it easy for the WW to sweep what she's done under the rug instead of confronting it and becoming a better person. It is only if you don't want to reconcile and are concerned that exposure may adversely affect your divorce (e.g., she loses her job and you end up paying more alimony) that one should be concerned about exposing the affair.
... there does not seem to be convincing actions on her part.
Great observation. From now on, don't trust anything she says. Only rely on what she does and doesn't do.
I don't want our kids to know for now due to the fact that it will most likely effect their studies.
This is a tough one. As noted above, exposure is key to ending the affair and creating the possibility of reconciliation. On top of that, you kids deserve to know the truth and will resent it if they are kept in the dark for long or if they learn about this from someone else. My advise is to tell them ASAP and no later than when their current school period ends.
I really want to understand why those who do this most of the time lack remorse. How can someone you dedicate decades to your lives too jump into someone else's arms/bed and only show happiness about it?
I am going to go crazy trying to find the reason though. I am slowly but surely realizing that this isn't my fault.
Why some people cheat and others don't is the $64,000 question and the truth is that you will probably never know why she cheated (she probably doesn't even know). So, instead of worrying about this, better to focus on what you can do to become a better man. This will increase the odds of saving your marriage and, if that is not possible, will set you up to find someone else to be with.
Yes, it not your fault that she cheated. But that doesn't mean that you shouldn't try to become a better person. I recommend you read the following:
"No More Mr. Nice Guy" by Robert Glover (you can download a copy for free at https://7chan.org/lit/src/Robert_Glover_-_No_More_Mr_Nice_Guy.pdf).
"The Married Man Sex Life Primer" by Athol Kay (https://www.amazon.com/dp/B004W0IRQ8?tag=viglink21103-20).
The first book is all about overcoming personality problems and weaknesses that lead to codependency. The second is about male and female behavioral traits and how they affect relationships. The information they contain will not only help you deal with your current problems, it will help you avoid relationship problems in the future (whether with your WW, should you try to reconcile, or with you next partner).
Wishing you the best.