<human>: Can you condense the text into a few key points?

**A small preface**

We have been going out for about 4 months now. She had a long distance boyfriend until the second month we were going out. She has gradually stopped having feelings for him, she tells me, until the point were I'm the only important one for her.

**The Problem**

I have become too jealous, and I can't help myself. For some fucking reason I tend to create problems where there are none, bringing up her ex again and again, and asking why she doesn't love me the way I do. She has even returned her flight tickets she bought about 5 months ago to visit him, to show me how I'm the only one who's important for her.

I really don't want to be like this, so any advice would be helpful.
<bot>: Seeking advice on how to deal with my own jealousy towards the girl that I love. Any suggestions on other subreddits to post this are welcome.