Getting Ghosted

I had sex with someone a few days ago, and we went from talking consistently to now not hearing anything from him at all. He and I had a bit of a D/s relationship, I was obedient to him and felt incredibly close to him because of that high level of trust. We had been having this thing going for over a year. We finally had sex, which was super awkward because he tried to do it outside with me near a interstate and I said no so we did it in his car, and it was so hard to get comfortable or relax especially since we're both fairly tall. When he dropped me back off where we met he didn't really look at me and didn't touch me to hug me or anything, just went our separate ways. I feel really confused and sad, because I put so much trust in him. I also am worried that he gave me an STD because I'm having burning pain in my vaginal area. He is in a relationship with a woman who has a child, I assumed it was an open one since he's into polygamy and cuckoldry but now know she doesn't know and thinks he is loyal. I truly don't know what to feel or do, because I'm losing so much as a result of this and he loses nothing and gets to keep his relationship and reputation, wh3reas I'll look like a whore.