I 32F found a tube of lipstick in my boyfriends 39M car and now I am spiraling

Just as the title says I 32F found a tube of lipstick in my boyfriend’s 39M car. I found it in the back when I was putting groceries on the back seat of the car. It was on the floor under the drivers seat in back.

He seemed genuinely confused when I first asked him about it. He took a picture of it and sent it to all his female family members to see if it belonged to them. They all denied that it was theirs. The lipstick was old and dried out. The tube was even hard to open because it was so old.

His reaction after this is what freaked me out even worse. I was quiet and tearful and he became defensive. He accused me of planting the lipstick in his car. He insisted that if I don’t trust him we should just break up.

He’s had his car for about 5 months. It’s a newer 2024 or 2025 Lexus, and the previous owner was female. He suggested it was left in the car from a previous owner. Is this even possible? Wouldn’t a Lexus dealership deep clean their cars before selling them? He also has a bad habit of leaving his car doors unlocked. We live in a big city and his car has been broken into multiple times because of this. He’s also had the car serviced multiple times.

We haven’t had sex in 4 months. I once found sex toys he said he “bought for me” but he never talked to me about them or showed them to me. He blocked me from his IG story last year.

The more I write about this the more I feel like I already know the answer. Is he cheating? I am an anxious over thinker, and I do tend to always think the worst.