I need help in my relationship asap!!?

ok im been in a relationship with this girl for almost 3 months and it was a tough road to get us together. Anyway she cheated, orally with anther guy although she claims it was brief. Still it happened,and i was very upset,but i cont the relationship. Which was hard,and she claimed she wouldn't put herself in that situation again,or cheat again. Come to find out again recently after we had a great day prior(no arguments) she put herself in a weird situation again. This time with a guy she pumped into in the club that she's know in the past. Who when she talked to him about me promised she wouldn't go out on a date with,but a few weeks later she basically does. While i was working i might add. At 1st she told me she was going out with her cuz later it was friends,but now i feel it was just him and her. With that he took her back to his house late 2 3 in the morning. She claims though nothing happened although she came home freaking 8 in the morning. She last texted me at around 2 am,but was texting me all throughout the night claiming she's missing me,and that she feel asleep at his house and only reason why they went there was because she got a buzz and didn't want to waste it(watever the means) She claimed he did try stuff but she pushed him away every time,but come to find out she fall asleep at his house IN HIS BED!!!!,but nothing ual happened at 1st,but later changed her story a bit. Like she told me he seen her or and he showed his ,and while she was sleeping in his bed they both took there pants off leaving both with just her under wheres. And in the morning he kissed they shared a long kiss (whatever that is),but that's all she claims happened. Like I really want to believe her because lately she's been claiming she loves me,but i'm not sure if I should just not trust her story and dis cont this relationship,bec after the 1st situation she promised me she wouldn't do it again,and she basically lied twice also lie to me saying she wouldn't date this guy. I do care for her a lot,and i don't want to make the wrong move i'm really lost and not sure what to do. im 25 she 22 should i just let it slide once again and not make a tiff about due to her age and still wanting to see if being with me is the right choice for a long term relationship idk what to do anymore. I treat this women good i feel and we do have a lot of great times, still when is enough enough.