this is VERY interesting consideration, I absolutely understand why it's been consuming you. thank you for sending this it made me want to rub my hands together like a shitty little fly. I wrote way too much about this

here's my take: I think it depends on what "obsessed with" means for you and why it's a problem for you specifically. like is obsession just wanting to talk to this person all the time, feeling a connection/like you "click" naturally, thinking about them all the time? bc that's all neurochemicals telling you to stick with this person! that's a huge part of what we know chemically as Love! so in and of itself I think it's normal, fine, and honestly fun and some of the best parts of being a human being tbh. BUT I can see why this would be an issue if the person you're into doesn't feel the same way/feels the same but not as intense/is stringing you along or you're otherwise getting hurt, and you're sick of getting hurt and want to do something about it. in that case I don't think it's the obsessive feelings that are the issue, but the person and the nature of the relationship you have with the person you're obsessed with. in this case I do think what your therapist says has legs: if you keep being obsessed with people who aren't obsessed with you back, give someone a chance who doesn't inspire those feelings at first and see what happens? BUT!!!!

I think if you've been on a couple dates with someone and you're not feeling a spark, there's nothing wrong with moving on. it's true that you may grow to love someone you didn't initially click with, but if you consistently find someone boring or conversation doesn't come naturally even after spending considerable time together I don't think there's a point pursuing that tbh. like if you don't even find them interesting as a friend, I wouldn't push it. I do know that sometimes you can grow to be REALLY into someone you didn't really click with at first but I think you'd know if that has a possibility of happening after spending a few hours with them. so the advice has legs but also kind of depends on the situation

here's the other thing: if the issue has been that you keep having intense relationships that start obsessively but fizzle out, and your goal is a successful long-term relationship I DON'T think it has legs. I think that initial obsession is just your brain being like I CHOOSE THIS ONE and what happens with the relationship longterm just depends on you and the other person and how you choose to deal with it. my partner and I absolutely started off mutually obsessively, I was absolutely smitten with this person and remember thinking (like 3 months into dating) "man if they asked me to get married rn I would literally do it tomorrow. I would literally do it with a ring pop." those obsessive feelings have gone away after 5 years but it's replaced with deep companionate love and trust, and we still have just as much fun and happiness together as we did at first. I think a lot of people get freaked out when the obsessive phase passes and they interpret it as falling out of love (and yes of course this can also happen) but imo most of the time it's probably just the nature of the feelings you have changing and that's normal. so to answer your question about obsession not being indicative of a successful long term relationship: I think it absolutely can be! just depends on how those feelings change over time and how you react to them.

SUMMARIZED: I think you can consider giving someone a chance who you aren't obsessed with, but if you don't find yourself growing feelings or seeing them in a new light after spending some time together I personally wouldn't continue to pursue that. and initial obsession can absolutely grow into a successful LTR and just depends on you and your relationship!!!

hope this helped lmao I tried my best.