I always forgive him so he thought I would forgive him again this time.
I always forgive him so he expected me to do the same thing again this time.
この場合、次のような言い方ができます。
ーI always forgive him so he thought I would forgive him again this time.
「いつも彼のことを許すから、今回も許すと思ったんだろう」
ーI always forgive him so he expected me to do the same thing again this time.
「いつも彼のことを許すから、彼は今回も私が許すと期待してた」
ご参考まで!