reposting for more thoughts from anons

how do you deal with being in a talking phase with a girl knowing she has current fwb? she has told me a bit about him, he's older and they met on tinder. they've been seeing each other a few months.
we hung out the other day and basically confessed to each other that we're both interested in something, but have some limiting life circumstances that are keeping us from being together fully.

so we're texting and stuff, whatever. but yesterday I asked what her plans were and she refused to tell me. her awkwardness around the questions (I did just some light probing) made me conclude that she's going to see her fwb, and obviously she doesn't want to tell me that.

I know we're not together, we're far from official, and she's not my property or anything but I can't stop it from bothering me, knowing she's getting fucked and kicked out while I'm doing boyfriend shit like taking her out (though she bought me dinner a couple weeks ago).
the thing is she said she's interested in more with me but like I said we can't really be together right now so we agreed to just keep it casual and see what happens in the next few months.

When we were hanging out the other day she brought up sexual stuff first by asking my body count, if I'm a player etc. she also appeared to want to kiss me but I didn't go for it.
so far I've concluded I should just try and fuck her (we're supposed to hang out tuesday) and if she's not up for it then I'll just cut her off.