I need advice ladies

My boyfriend and I were madly in love, we live together and genuinely enjoy being with each other. Recently, I learned he had been on a dating site after a drunken night, flirting and measaging girls. Since I found out, he’s given me full access to his phone and all apps, messages, etc.. and is taking break from drinking. but we don’t feel like our normal happy selves. This was all very recent (less than 48 hours ago) so I’m not sure if the sting of it is effecting our relationship or if this is how it will be. Obviously there is no trust and he wants to earn that back. The advice I need, ladies, is has anyone gone through anything similar? How did you regain trust and get your relationship back to what it was? I’m more heartbroken that we aren’t our normal selves than I am about the actual incident... I miss us being “us”.