Need advice on recovering from infidelity

I been married 11 years, no kids. My husband cheated 3 times in r relationship. last time has been 3 years ago. i cheated 4-5 years ago one time. Anyway, since then, we both received counseling and changed our ways. are communication has gotten so much better in the last 3 years. He is attentive, caring and loving. he is the man i always wanted him to be n vice versa. he is very transparent too. My question is how do i get over this. the first two times was painful the third time made me not feel aa connected anymore. i trust him because he is transparent (picks up phone, changed his loser friends, goes to bible studies with me, church, respectful). i barely bring it up but it is in the back of my mind. I feel like why did he not change after the second time. How do I let go and put my guard down ?