How to get over the pain and anger of being cheated on by my wife.?

Ok here's my story last week my wife told me she only loved me as a friend for the past 3 to 4 years we have been together for 6 years.Then she got pregnant with our son and she and thats the only reason we got marred cause she was pregnant not out of love at all. Then a year later she got pregnant again with a girl she told me she tried to make it work in her head after the first one and even harder with the second one. We have been marred for a 1 1/2 and then she told me she has been cheating on me a month after we got marred with this prick at my work that i know. Then she hit me with a nuke she told me that the girl she just had most likely might not be mine. I just need some help on how to get over her it's just so hard to see someone you have been with for 6 years to be with someone else. It just make's me want to kill myself but I don't only cause of my kids even if the girl isn't mine I don't care I will still treat her like she is mine. I need to clear this up the boy she had is 15 months old he is the oldest and the girl is a little over 3 months old sorry I didn't explain enough.But still it's hard to get over and I just don't know what to do I thought she was the one but she didn't for me. And I will never kill myself that's just how i felt but i will never leave my kids they are the most important to me both of them. I was a good person to her I treated her like a queen. Like when we first got together I would do anything for her and I still did up till now. One of the excuses she gave me for getting with the other guy was that we didn't have anything in common but that's what I thought made us special cause opposites attract or so I thought. So thats why she got with the other person cause they had more in common. She also told me that when she started cheating on me after she had the our son she was hoping I would sleep with someone else so she wouldn't feel so bad. She was my best friend I would cook her dinner what ever she wanted every night when she was pregnant and when she wasn't gave her foot and back when she was pregnant so she would feel better. The person she is with now is just a user someone who never wanted kids openly. This person is just a bum who knew she was marred and had a family and still hit on her he has done this to other people before. So if anyone could help that would be nice and thank you.