Avoiding a new relationship at this emotionally fragile time sounds like sound judgment, all thing considered.
Might it be better to focus your time and energy on healing yourself and children from the very real trauma of living with someone active in addiction?
No idea what kind of program your husband is in or for how long. Rehab is not a cure. The real hard part starts afterwards and he owns his own recovery.
Perhaps one on one, face to face, counseling can help you decide if you can accept your husband as he is instead of how you want him to be.
As it relates to the infidelity thing, I am one of those who believes that confessing serves only one person, the confessor. There may be healthier ways for you to manage the guilt.