He did it again

Hello ladies, I post it here because I need to let it out off my chest. I just found out my husband cheated on me again this is the second time I don’t know what to do. It happen like 2 year ago but I just saw it in his old phone all the messages they send it to each other. He said it been over for a long time to make it worse I know the girl he cheated on she is married and right know she is pregnant. He said he is going to change and that he sees us in the future with our kids and all that crap that right know I don’t know what to believe. What should I do should a let her husband know?

Should I take him back? Again... right know I’m just loving my self and my kids and taking it one day at the time.