Jewish Geography can become an issue when you’re single and seemingly connected to nearly every other single Jew that you know in some way — either you hooked up with their friend, or your friend dated them seriously, or your cousin broke their friend’s heart — and suddenly you feel like there’s no one left to date! But really, very few single Jews are truly “off-limits,” and even then, someone can usually become fair game with a simple conversation.
Ex-spouses of your friends are off-limits… unless it’s been years and they’re now friendly and your friend, in fact, set you two up. If it’s an acquaintance’s ex-spouse then it’s perhaps a good idea to run the idea past your acquaintance before pursuing a relationship. For example: my fiance and I were set-up by a mutual friend who is also good friends with his ex-wife. Our shadchan asked the ex-wife’s permission before making the shidduch.
If one of your friends has never recovered from getting dumped by someone, then that person is probably off-limits. If one of your friends contracted an STD from someone, then that person is, well, need I say more? But if your friend simply casually dated the person, then a simple phone call asking for your friend’s blessing should suffice. And if there was no drama and yet your friend won’t give you permission, then perhaps you need to take a deeper look at both the prospect as well as the friendship.