I had sex with my professor and now I miss him (*gay*)

I am a 21-year-old gay student currently attending an international college in Japan. The professor is a Japanese who teaches classes on communication and stuff. We got to know each other through the app called Jack’d which is quite popular in the gay community here in Japan.It was me who initiated our first conversation on the app by saying hi, and to that his reply was “Nice to meet you. I work for your school so we can only have socially appropriate relationship. The best I can is to be your mentor”. I was taken aback because he knew that I am attending the school yet still I felt intrigued because no one had ever replied to my message in such a way. Then we exchanged messages and found a lot of common things in each other and on the second day, he asked me for my number so we could use whatsapp, which is much faster and convenient to chat.He is kinda busy and has to travel a lot especially during school breaks when he got to do a lot of school promotion thing. So basically on the third day, he was gone. We continued our communication on whatsapp when he was away. The more I got to know him, the more I felt interested in the person he is and somehow I sensed that he is feeling the same way too. So the whole socially appropriate warning from the start gradually eroded once we started exchanging flirtatious messages to each other. He likes it, so do I. He thinks that I am a very strange student, considering the context here in Asian where pedagogical ethics are so crazily revered, but that’s what he is interested. I know from him that he has a boyfriend 29-year-old, who is Taiwanese – the fact that poses a huge challenge for them to really get together. But still, I don’t care about that because I believe love is a game and I find no shame to go for what I want even when it is already taken. Nothing lovely and desirable would come easily.Two weeks later, he came back to town at 6 p.m. after a long day of traveling back and drove his car to pick me up at 7. We went out drinking that night. Once both of us got pretty drunk, I noticed he started kicking my legs yet I remained pretty calm and tried not to show overtly stimulated while in fact I was. We chit chatted that night and departed with only a hug and no more. Both of us felt good about it and somehow I grew to like him even more.He flew off somewhere else for work two days later and the whole episode of chit chat on whatsapp got repeated until our next face-to-face meeting. This time, we went out drinking again. (Yes, I love drinking so much because his unavailability really gets me frustrated). We got drunk again and this time he invited to his place saying that I was so drunk to get home by myself. He said I could sleep on his sofa while he in his bedroom. The idea of sleeping on the sofa is pretty dumb I supposed but I said yes so that I could get into his apartment – which was all what I wanted (till this point, I felt so much wanting to make love to him. His now-and-then mention of his boyfriend did make me jealous and of course want more). We entered his apartment. I lied on the sofa showing a sulking face asking him whether I could sleep with him on his bed. Without hesitation, I told me to come over. The moment the light went out, I turned to his side kissing him on his cheek and smiling drunk. Before he had told me that lips are off-limits because once he kisses anyone on the lips there will no way back. And because of that, I want our lips to be touched. After a few moments trying not to, he finally turned his head in kiss me on the lips. And that was also the beginning of the whole session afterward, without which I would have not known how good he is on bed. He was so passionate and aggressive at the time. My whole body seemed to turn into a totally different state, overwhelmingly stimulated by his touch, his kiss, and all of his other ventures over my body.It was two days ago when this episode happened and right now, strangely, I feel like his existence is all over the place. He texts me saying that he likes me but he also loves his boyfriend. We are not really in any sort official relationship. Everything is still pretty much a matter of speculation of what may turn out. He told me he is concerned about his professional ethics, this and that, which I often disregard as something superficial. I feel like I’m struck by not only his intelligence but also the sex – which I find the most passionate and satisfactory till date.Still, I am very much skeptical about his motives. He is much older than me, a 36-year-old gap. And for that I suppose he doesn’t always say what he really means, yet he still seems to be very honest to me.Am I a little bit wrong and disillusioned in this whole thing? I would appreciate any comments, either positive or negative. I am thick-skinned enough to take it all.