Is a second divorce and renewal of the waiting period (iddah) obligatory if there was no intention to reconcile with the revocably divorced wife, but ejaculation occurred as a result of touching her penis during the iddah?

The preponderant view, according to us, is that a return (raj'ah) does not occur through a man’s enjoying his wife without intercourse. So, if he kisses her, or touches her with desire, or uncovers her private parts and looks at them, this does not constitute a return. Therefore, your wife has not returned to your marital bond, and it is permissible for her to adorn herself for you as long as the divorce is revocable (raj'i). However, if the divorce is irrevocable (ba'in), she is a stranger to you, and it is not permissible for you to touch her or be alone with her.