My Lover and me Broke Up Again, HELP?

My on again off again relationship with my gf is getting to me now. We live long distance and when I went there the last time I found lubricant in her side drawer. I knew it wasn't from me and it made me sick to see it because in my heart I knew she had someone else there. We are s. I didn't question her but I was standoffish. Then I found her name on a personals looking for someone else and so we got into a fight. She never pays for the personal ad, she's too cheap she just gets the flirts or kisses that are free. Anyhow, I got home and we argued and I hung up on her. I then emailed her on all I knew. She emailed back and basically said that it's not true it's not her on the personal site which is a lie and said NOTHING about the lubricant. I've never hung up on her. She's always hung up on me and said it's over. I did it this time before she could. She kept sending me emails yesterday and I wouldn't respond and then I responded to one saying she owed me.