If you want people to give you the answers you want to hear, you should focus more on the topic you want to be discussed.

Your entire post is nothing but you going on about your insecurities and how you're hurt and you feel betrayed and theres not trust anymore, which is basically what people say when breakups have happened/are going to happen, and you only mentioned "accepting your feelings" like twice. This is why you got the answers that you did.

Anyway. You can't just "accept" these feelings. You can't come online, tell us your story and then ask "How do I accept these feelings and get back to where we were?" This isn't something you can do. A random person on the ineternet can't be like "Oh you have to do XYZ and tada! Miraculous relationship cure!". IT takes time, communication and it takes the both of you.

You need to get to the real reason why he did it. His answer seems totally made up, and if it is the truth then damn he needs to learn how to manage his stress better. And you need to learn to be more firm. I'm sorry but by just up and forgiving him like this you basically taught him that he can do whatever and leave you whenever and you'll always take him back no matter what.

You need to communicate with him and basically tell him everything that you JUST told us. How the trust is gone, how you're scared everything and anything will cause him to leave you now, how you're not sure how to feel anymore, hell just show him the post if you have to. He needs to hear from you how you feel. And you need to let him know what he has to do to regain your trust. If you don't communicate with him and give yourself some actual time to heal and not just a few days/weeks, the doubt and constant mistrust will eat at you and eventually destroy your relationship.

The both of you acting like this never happened is just pushing the problem to the side, allowing for it to grow and become a bigger problem. This isn't so much as a "How to deal with breaking up with getting back together again" situation as it is a "How to heal from broken trust." situation.

"How do I accept these feelings, deal with them, and get back to where we were? I want to trust him again."

Speak to him. Work it out together. Give it time. Therapy if needed. Talk to someone. Set some boundaries.