Had a really vivid dream that is eating at me.

In the dream, I was hanging out with my boyfriend and my sister, trying to find something to do. We were at someone's house, one of our houses. So my sister mentions something to him and he nodded and said, "alright". Then they left together. I was confused by how I didn't get invited, so I thought something was fishy. So as they are minutes ahead of me, I follow. They left out the front door, then I did. They didn't know I was following them. As I go outside, I see a big van in front of the house, windows covered, but one door open. Which I see them naked in that door looking through a drawer that's inside of the van. Because they are naked, I'm confused. But I enter and to the left of me is my boyfriend who is currently naked and holding a dildo. While my sister is to the right of me, naked, searching through the drawer. But turns around after hearing me enter. My boyfriend didn't even seem fazed. He stood there proudly as I asked what was going on. He said, "cheating on you." I asked my sister, "why would you do this to me?" She said, "because he's hot, look at him." My boyfriend said, "I know, look at me." (Which in real life, I agree, he's extremely attractive), then I said, "I knew it!" Then I woke up with my heart and mind racing. Because it was so real, my mind is playing with me like it was real. It's hard to talk to him right now. I don't think it was a clairvoyance. I think it might just be because I haven't had a good amount of alone time with him lately and he's been hanging out with his friends a lot. Am I wrong to start keeping my eyes open to see if he really is cheating? Not with my sister (she's in a different state) but with anyone else.  I don't believe he is, but he dream keeps making me feel as if he could because he is attractive. Should I just not listen to the dream? I don't know anymore.