How can someone

Lie for over 7 years to you daily by having you think they are faithful to you but the whole time they were cheating behind your back? I'm saying numerous RANDOM people the entire relationship. I loved you. We planned and tried for our child. Now he is all I have. Nothing is what I thought it was. How and why can people do this. I thought we were in love. I don't ever want to feel like this again. I never would have cheated on you, not EVER. You promised me you would never do that or hurt me in the ways others had previously and that we would be together forever and that I was all you wanted.