If truly remorseful, your H will make every effort to rebuild your trust and aid your recovery from the wounds he has inflicted.
He must cut contact with OW. They still have feelings for one another and have had physical and sexual involvement. Their continued proximity will have a detrimental effect on your emotional health, so he needs to find a new job..
He must take complete responsibility for his infidelity without shifting any blame to you. (Saying he couldn’t talk to you is deflecting blame.) If he had issues, he had a range of ethical options to use to deal with them, but he chose instead to develop intimacy with OW, cheat and lie.
He must provide full transparency with all devices, phone bills, bank/card statements, etc. He needs to take your anger and tears and answer all questions whenever they come. He doesn’t get to set a time limit on your grief. It can take 1-3 years for trust to be restored, and it may never return.
Can the messages be retrieved? I would want to see everything to know what I was forgiving. Likewise, I would insist on hearing what he told OW regarding his feelings for her and their future, as well as what he said about me and our relationship. Otherwise, they still have their secrets.
He needs to seek individual counseling to examine his weak boundaries and sense of entitlement to pursue an illicit ego boost and cheat. Remember that the character flaws that enabled his infidelity are still present.
You would also benefit from the support of individual counseling to express your thoughts and feelings as you move through the grieving/healing process.
Personally, I would end my marriage if my husband betrayed me in this way, as my trust would be forever gone.