Helppppp meeeee

Ca

Me and my bf have been together almost 5 years, we’ve been through some rough patches but we have been amazing ever since. Recently I found a video of him making out with a girl who he said he never liked at all or have done anything with. He lied. I don’t know what to do. He said he didn’t want to hurt my feelings and it wasn’t when we were together. Please tell me what I should do because I have no clue. I’m just super hurt and disappointed and he has used that line before after he promised there were no more secrets