Visitor Visa - B2

hi to all!i want to share my sad experience about visa refusal,i was interviewed just this month ,the consul asked me as to who am i going to visit in the US so i told her my bf's name,then she asked me my ex fiancee's name and i told her that he was my ex,im sure they knew it from their database that someone from b4 filed a petition for me,i never expect that they would ask me about him i was surprised,btw,he filed a fiance petition but when my interview date was scheduled he never talked to me nor told me that his gonna break up on me..(sad)i dont have an idea if he called or emailed the embassy as i told him to let them know he's cancelling the petition.because i was depressed i never had the chance to call the embassy,i never showed up during the interview sched.(it was a sad past)now i met a guy and we've been in a relationship for 3 yrs now and hes inviting me for a vacation and wanted to bring me to disney and other part of US,my prob is i got denied.can reapply for a visa again next month?is there any effect from my previous petition,after all it was not my fault?i have a good paying job for 2 yrs now,do i still have the chance for a tourist visa?how can i prove to them am not going to stay in america for long?will the invitation with a promise to take care of the expenses from my boyfriend works out?