It isn't your perogative whether she feels guilty about it or not. You're only worried about her feeling guilty incase it ruins things between you and her. You don't need to concern yourself with that - if she feels guilty, tell her it's cool and give her space. She'll come back. Whatever you do, don't comfort her and tell her not to feel guilty and that everything will be ok etc... that's bullshit and will get you nowhere.

As for actually getting with her, she's displayed to you verbally that she likes you more than him. Does she touch you a lot when she's talking to you? I dunno what age you guys are but when people are younger, relationships for the most part are very short lasting and when someone they like better comes along all they need to do is make themselves available. If you straight up ask her out she will most likely leave him for you... however if she's more mature this obviously won't work. Give us a bit more detail on how you get along with each other.

One more thing, what the fuck is with the strawberries? You don't need a special prop to use kino. Just touch her when you talk to her. You should be doing this already anyway... all you need to do is go for longer instances of kino and see how she reacts, things like holding her hand, resting your hand on her lower back etc. Just think back to how things escalated with the last girl you slept with . All you need to do with this girl is escalate kino until you know she's getting horny for you then kiss her and go from there. Don't mention her boyfriend or ask her how things are going with him because it only reinforces the image of him in her head. If she mentions him, steer the conversation away and have fun.