Is being paranoid about infidelity or betrayal a BPD thing? It's killing me inside and I don't know how to address it or self-soothe! It absolutely destroys me. My boyfriend and I got into a pretty huge fight last night, and he traveled to a different city (across the border) with his friends today for a show. This was planned a month ago and he actually came over to be with me last night because he knew I was anxious, but we ended up getting into a really bad fight. He stayed the night and then left this morning. We had made plans to see each other again tomorrow but he left on a bad note and didn't confirm what was going on tomorrow other than saying "I'll call you or whatever!" and just stormed off. I texted him an apology and wished he'd have fun before they drove across the border and he didn't respond. I understand that he has no cell service there until he gets back. But I saw his friend tweet a picture of them together at the show and my boyfriend's wearing a cool t-shirt I bought him and I got this incredibly awful pang in my heart, and I started worrying about him being unfaithful or talking to/meeting other women at the show out of spite for me, or because of how upset he is with me. I can't get rid of this fear. Every time we fight I worry about him leaving me or hurting me, because he's done it just once before, a year ago. He apologized profusely and we worked through it but the way he is when he's angry really hurts me, which is why I feel so awful when he's gone and we leave on a bad note. I worry that he wore that shirt to get people (girls?) to talk to him (because the shirt has a lot of text on it and it's clever and funny, and he's a cute guy and this is a show for people who share a very niche interest/hobby)

Instead of thinking that maybe he wore the shirt because he loves it and maybe he loves me/wants to think about me, my mind jumped to thoughts of fear and infidelity. I don't know if I should admit this to him or how to talk about it. Is this my own fear to suppress? I don't know how to deal with this anxiety and these thoughts. They eat away at me. I have no proof for any of this, it's all unfounded and I know he absolutely hates being accused of these things so I won't accuse him. But I imagine him coming back and breaking up with me, or not telling me what happened at the show, or worse! I don't know what could be worse but worse! 

Am I insane for having these thoughts? I know my ex contributed to a lot of these worries because I could never trust him to travel alone because he actually cheated, but my boyfriend has not given me a reason to think this. Is this just my BPD coming out?