Bro', you seem like a pretty decent guy, so here's advice from another arm-chair observer -just frickin' do it!!! Forget all the B.S philosophy about whether you should or you shouldn't and and enjoy frickin' life!!! I'm saying this as one of the OLDER guys on this board (older than 45, but younger than 60!) What's wrong with just being a decent, red-blooded male who enjoys consensual sex with an adult female (or females, as the case may be) whom he finds intriguing and attractive? I mean, am I missing something here? If you are truly too mentally and emotionally f'ed up to do so, then you should seek professional help rather than the opinion of people on this BB (like MYSELF, LOL!). As far as I know, you are a healthy, hetero, American male who enjoys female companionship - duh! That female companionship need not be the next love-of-your-life - she can simply be someone that you enjoy sharing sex, conversation, ****-talking, or whatever with in the here and now. However, if it somehow turns out that way, that's cool too. And as an aside, the comments about one woman's suitablity (or lack thereof)for introducing to family as oppopsed to another woman's is not only premature, but it's immature. Until you've spent time with a person and engaged them in more than just casual conversation or observed them through more than casual observation, you can't even begin to guess at this! It's that old, male double standard in your own head that causes you to categorize these women as lady or not-a-lady based on your perception of each one's sexual attitude, number of past partners, etc...which may or may not translate into how each one will behave in a steady relationship (see your Ex for a reference point). As you know, everyone is multidimensional, and what each individual chooses to present to another is often determined by what they perceive about that particular person, and not necessarily "what they are all about."
It really seems like your confidence has been shaken by the soon-to-be-ex and the "revelation" that she's seeing/involved with someone else, which is pretty normal, BUT... you've got to get past that and focus on YOUR NEEDS. You're making a straightforward proposition by the 24 y/o into something that is wayyy too complicated. If there is a mutual physical attraction, AND both parties are being upfront about the "hey, this is just sex thing," then just frickin' do it. Otherwise, YOU are the one jerkin' the 24 y/o around because you are simple using her interest to pump up your ego and confidence by engaging her in talk, but not following up with action!!!
Keep it simple, don't lie, don't lead people on. and enjoy your health and good looks the way that any normal male would. Finally, you don't need to try to impress anyone else (yes, that includes all of us on this BB) with how desirable various women find you (and about one gazillion other men - duh!)- you simply need to be honest with yourself about what you can or cannot handle, what you desire or you don't, on a day-to-day basis and stop behaving as if any and every encounter with an attractive woman has to lead to your next "permanent" relationship!
Roger willco, over and out...