I f'ed up big time and don't know what to do

So here's the thing. I've had a boyfriend for 3 1/2 years now. He's Italian, I'm Austrian and we got to know each other when he was arriving for an ERASMUS semester to the city I live in. We come from different cultures and always had different opinions about our lifes and how to approach them, but eventually we started to love each other and are living together now since the last 3 years.In the beginning everything was awesome, I was the happiest person in existence. I even got all my guts together and came out to my parents about him, who started to accept him as well. We did travels together, met friends, went out for the nights and had wonderful bedtimes. Everything was like in a wonderful dream.But in the past half year sh*t started to get real. I lost my job and was at home for 2 months and fell into some depression which I am currently seeing an expert for. But my desires for my BF dwindled, our everyday life was complicated at best and travels stopped. My BF was still a student at this time, writing his master's thesis and having a full-time job next to it. He simply had no time anymore to do all the things we loved to do.As my BF doesn't have many friends here, I allowed him to use gayromeo as a platform to learn to know new people. Needless to say that's a bit of a problem because most people there are up for something else than friendship. Anyways I was using gayromeo too to find new people, and one day i found this guy who is totally the same as me. We had lots of fun writing together and once met for a beer. Then another one, where even my BF joined, it was a great time.Then my birthday came up and we all went for a drink or 2, and I got really drunk, which caused me to kiss that other guy secretly and tell him that I had feelings for him. My BF is of course not stupid and eventually found out. We had lots of dramatic scenes, tears, crying and the stuff, and as he has got nobody here in Austria he got scared and alone. It tore my heart into pieces seeing how much I've had hurt him.When he left for Italy to get his master's degree, I met the other guy a couple times and we kissed again and it made me fall in love with him completely. When we started to get down on each other he told me the twist: He's positive on HIV. He told me he got it from doing drugs and having intercourse with people he didn't know in earlier times, but it didn't matter to me, the damage was done. At the same time I booked a flight to Italy to see my BF and be there in the moment he's having his graduation, as I started to miss him so terribly and wanted to be part of that moment that finally marked the end of the studying stuff that controlled our lives in the past. I have very strong feelings for my BF, also because I am used to his presence and feel very comfortable with him around. But there's also that other guy, who is totally in love with me and for whom I have feelings too.Now there I am: Although the other one is terribly ill i cannot get him out of my head, thinking every wake second about him. For my BF I also have strong feelings left, and he even came back to me and is now living with me again. But instead of being happy about it, I don't know how to express my feelings. On top of that I am terribly scared I might have gotten something from the other one, which I might pass to my BF, which makes me very nervous and anxious. I feel like I am trapped between them two and cannot get out of this without losing both, which would be my biggest nightmare.TL;DR: I fell in love with another guy although I was in a stable relationship. Now the other guy told me he's HIV positive and I don't know how to react to both my BF and him, as my feelings are torn.