how do you forgive someone who hurt you?

I'm struggling to forgive my SO for lying to me about deleting porn on his phone and discovered that he paid for porn and was flirting with the girls he bought the porn from. It's hard cause I love him and know we can get past this but I'm struggling. I'm just in shock that he would ever do something like that to me. It's only been a few days since I found out. I know healing takes time but I still have a heavy heart about it all πŸ˜’πŸ˜ž