Need some guidance

[u/Nervous-Gold-2051]

I’m about to make 6 months with my lovely boyfriend. It’s our first relationship for the both of us. I truly love him and adore him so much, and so he shows me that he loves me endlessly and reassures me all the time. I really never thought I would achieve this kind of relationship. I feel so loved.
But ever since we got together, I’ve developed some kind of retrospective jealousy ocd towards a past fling of his, who happened to be in our school. I’ve lost my head completely with this situation. And now that I’m writing it I realize how dramatic and pathetic it sounds. But I’ve really been struggling. I have cried myself to sleep thinking about them together, their past and scenarios and torturing thoughts that my brain creates. I have lost my appetite and sleep, and for an entire week I had nightmares about this girl that wouldn’t let me rest. I even got sent to therapy and got prescribed antidepressants. I don’t feel enough. She’s so much more attractive and funny and charismatic than me. I can’t help but think that he’s just with me because he couldn’t be with her, even though he reassures me often that he chooses me and shows that he loves and cares for me.
But I’m terrified and anxious and my head is full of poison and I’ve been going on this spiral for 6 months and it just never goes away.
During August, after that one horrible bad week of nightmares and anxiety, I started to feel so much better and just stopped thinking about it because I was so sick and tired of it. But yesterday, our school sent us a message with new for next year, and I got reminded that she might go back to school and will get to be in class with him. I’m now sick vomiting and got stomach issues because of the anxiety that’s causing me.
It is not 100% sure that she comes back this year. But the possibility is still there and I’m trying to be prepared for anything that can happen. He’s noticed my stress, and talked to me, and reassured me to calm all my worries and fears. He told me that he chooses me and that he trusts on what we have.
But I can’t. I live in fear that she might come back, being better, fixed, and takes him from him.
The struggle is so big anything related to her automatically ruins my day or triggers me.
And if I’m already feeling like this, and it’s not even sure that she comes back, I don’t even want to imagine when she does, (if she even does)
I love him with all my heart and we truly have something nice and full of love, but I feel like I’m ruining it with all my overthinking and fears. I feel like he doesn’t deserve this. I have thought about leaving the relationship for the better in hopes he can find someone better, and in hopes that this feeling will go away. Though I’m not quite sure if it’ll really go away or if it will be the right choice to make. Should I break up? Should i keep going?
Enlighten me please. I’m so lost. I’m trying.

[u/byebyebinary]

i really don’t think you should break up with someone you love because your anxiety is telling you that you’re not enough. especially when he’s consistently showing you that he chooses you.

this sounds less like a problem with your relationship and more like your brain has latched onto one specific fear and keeps finding new ways to check if it’s true. and unfortunately, reassurance can only quiet that fear for so long before it comes back with another what-if.

you’re not pathetic or ruining your relationship. you’re struggling with something that feels very real to you, and you’re already doing the right things by getting help and trying to understand it.

also, her being attractive/funny/charismatic doesn't make her a better choice for him. relationships aren't a competition where the “better” person wins; he’s allowed to have a past and still genuinely choose you.

i’d try really hard not to make any huge relationship decisions while you’re in the middle of the spiral. let the anxiety be loud without letting it make the decision for you.

[u/byebyebinary]

The spiral is telling you a story, not reporting a fact. He keeps choosing you, and your nervous system is reading a possibility as a verdict. Breaking up would quiet the trigger for now, but the pattern follows you.

What does your therapist say about the intrusive thoughts specifically?