My girlfriend is shadyyy?

Me & my gf have lived together for 10 months. Recently, she was at work & left her phone at home, she got a text from a guy asking how her new job was( the job which I got her btw because I work there also) so I tell her I want her to leave my house for basically being with another guy by texting him. So two days pass, she keeps begging to come back because she's sick from missing me so much. I guess I realize that I must love her if I miss her, so I buy a ring & when I ask her if she wants to come over for sex, I'll ask her to marry me. So I did. And she's cryingsaying how happy she is, well, in the shower she tells me that she went on a date with the guy one night while I was at work, and that she wants to be truthful to me from now on. I mean, I just don't know what I should do. I really don't feel the same torwards her, or really feel like I'm able to trust her again. She's also punched me in the face on 6 different occasions, and she always says she'll never do it again.....ughhhh Idk....Idk.