My Husband confessed that he have feelings for someone else

I have been with my husband for 4 years, and we got married 2 years ago. For the past few days, he has been avoiding me. He says he's tired and goes straight to bed, but I had a nagging feeling that something was wrong. Last night, he told me he needed to talk about something serious. He confessed that a few months ago, a new girl (25F) joined their team. Initially, their conversations were strictly work-related, but they began hanging out more, going for coffee, and he realized he might have developed feelings for her. He has since stopped going out with her and only talks to her if it's work-related. He said he thought he could keep this to himself, but he couldn’t hide it any longer and decided to tell me. I don't even know how or what I should do in this situation. We've never had any trust issues between us, and I would never have guessed that he would do something like this. I don't know how I can start trusting him again