No, that is not valid.
As of this posting, annulment is the only remedy available in law for ending marriages. It has been held in many SC-decided cases that such declaration alleged by your husband has no legal effect and it is a waste of time.
Chats, call logs, messages, witness testimonies are just a few of the evidences possible in order to prove the infidelity of your husband, but unfortunately it is not a ground for annulling a marriage. Infidelity is a ground for legal separation, but it is only physical separation and both spouses CANNOT remarry.
At this point, hiring the services of a family lawyer is best so that he can assess the evidences you have on hand and if your case can prosper in court.
Godspeed.