You already cheated (poorly) and she took you back and used that guilt I'm sure you built, to get you to move in with her. So a few things. Don't care how loyal she is. She's gonna cheat right back. Humans operate like that, women just happen to cheat worse. If you know you were gonna cheat, no point in giving up the rest of the stable. You already tested to see if you're mature enough to just do a 1 on 1....that failed...usually does for young men. More importantly, don't assume that she shares the idea of your "sacrifice" of giving up other birds in your life. It means nothing to her, she'll still find other men and resent you for cheating. Essentially, stop being so weak. Plenty of women on the planet. Learn how to cheat proper, or don't bother with the relationship. Juggling isn't your forte, best lean on bootycalls.
BREH...... let her go and save yourself the potential heartache. 
