What can I do to trust him but most important what can I do to forgive myself?

Things happened the way they did because that was the way they were meant to happen. You loved him and wanted to be with him forever. Now you are. You have a precious baby on the way. A miracle and now you are related by blood to him. You've gone through a lot of life changing events all in a short time. But calm down, count your numerous blessings, quit looking for trouble and start showing him you love him.