How does one let go of anger. when it is from the past.?

See one I first meet my boyfriend , he bragged about his ex girl friends , job ( money) and ex wife how preety , her job and how good she can deco.. and it was other women too .Always something they are good at. So I asked him why would you say that to a girl you are dating and he said he rad a book that said that is what women want to hear and I told him I have never heard of it. and he said his friends suggest it too. ( married friends by the way) but still it hurt and went on for long time. but not as much now cause I told him it hurt ,but he thinks I am wrong and that my past has caused my feeling about this. does everyone agree to this or am I right you just don't say things like that?