What would you do if your girlfriend did this to you?

Last sunday, my girlfriend and i broke up. during the whole duration of our relationship, we couldn't hardly ever hangout. she always said "her dad wouldn't let her" or she would use an excuse like she had to clean or had too much homework. and for weeks and week i put up with it, thinking it would get better. well while she wasnt able to hangout with me, she was hanging out with this other guy (we'll call him jon for privacy's sake). So Jon and my girlfriend are hanging out on weekends while me and my girlfriend cant. i didn't choose to think anything of it because i believed her when she said that her dad wouldn't let her hangout. so this past weekend, her and jon got to hangout and we didnt. and we broke up last sunday. so 5 days later Jon asks my ex gilfriend out and she says yes. so now they're dating. 5 days after we split up. i dont think there is anyway things can materialize between 2 people to start dating in 5 days. less than a week. i know that she had already decided to break up and start dating jon, but she denies every word of it. she says she didnt lie and she didnt cheat, and she didn't want to lose me as a friend. personally, i think if she truly didn't want to lose me as a friend, she wouldn't have pulled a stunt like that. ya know? and now she's calling me a hypocrite (for what reason i have NO idea) if anyone is the hypocrite, its her. what would you do if you were in my shoes? (sorry this is so long, there are lots of petty details to the story that needed to be told).