Welcome to SI and I'm sorry that you're now part of the best club nobody wants to join. We do have members that fall within your situation. It can be hit or miss when they're on the site.
If you haven't checked out the posts pinned to the top of the JFO (Just Found Out) forum, please take the time to read them. There are also some great posts that have bull's eye icons that are really good. The Healing Library is at the top of the site and has a lot of resources.
I'm sorry that he turned a time that should be joyous for you and made it a time of misery instead. If you can, IC (individual counseling) with a betrayal trauma specialist can be helpful.
Please take this time to take care of you and your child. Focus on you and your healing. If you're feeling depressed or can't sleep, ask your doctor for some meds if you feel you may need them. While you're there, you may wish to be tested for STDs/STIs, and your WH (wayward husband) should as well. There are some nasty diseases out there.
Be sure to eat healthy and stay hydrated. Expect your emotions to be all over the place - we call it the emotional rollercoaster. Exercise can help get rid of your anger.
The self-esteem takes a hit when you find out your spouse has been cheating on you and isn't limited to people who were pregnant and through babyhood. His A (affair) wasn't based on how you looked or didn't look, said or didn't say. He has something wrong with his moral compass and the decision to cheat was his choice. Rather than talk to you about things, he selfishly thought only about himself. He should be in IC to work on his why's.
Look at all the gorgeous actors & singers who have been cheated on. Halle Berry, Jennifer Aniston. Adam Levine's wife was a Victoria's Secret underwear model.
Sorry that you're here and I'm hoping others will post.
BW M 34years, Dday 1: March 2018, Dday 2: August 2019, D final 2/25/21