Confusing Behavior

A girl I’m dating is always “busy” when it comes to texting or calling, and replies to messages after hours. I match and mirror her actions, and focus on filling up my day with activities and hobbies to not let this affect me. However, when I’m with her irl, I see her using her phone every 15-20 minutes either messaging people or replying to messages.

Also, I noticed yesterday that she’s very secretive about her phone. I’m not one to pry into a partners phone, but I get this off gut feeling that she’s probably talking to other guys. What’s the best way to approach this situation?

For context, we were broken up (she broke up with me due to issues in long distance), however we’re now in the same city and she told me she wants to give things another shot. I’ve been focussing on HHH, but haven’t explored other options yet.

She hasn’t bought the “what are we” conversation yet, but always asks me if I’m talking to other girls or says comments like “do you want to get married to me”. Her actions confuse me a lot, because when we spend time irl, it’s really good, but when we’re not, I feel like she ignores my messages or barely shows any interest.

I’m so confused what to do because I feel breadcrumbed by her and I don’t want to not explore other options if we still don’t have a label yet. How do I approach this situation and do I talk to her about me exploring other options?