So.. here goes.. my story is quite complicated and long so be sure u have time to read as I'm searching for a specific answer I'm writing down all the details... :

Ive been going out with Mr.X for 3years now.. I considered him not only as my lover but also as my best friend.. problem was he was really jealous and we would use to fight a lot over the stupidest things and eventually I couldn't take it anymore but I ddnt do anthing yet...
Im not the type that enjoys going out a lot.. most importantly because I am used to the same people but in summer.. I met some new people different perspectives like a new world that's when I decided I needed change.. and so I broke up with him
but it wasn't like we ddnt talk on the contrary we would always talk.. so the pressure/tension never really went.. he would always see who I was talking to what we were talking about etc.. It was so annoying that I began to erase my msg's my phone history and then..
2months ago I started talking again to an old friend Mr.T.. who 2years ago was in love with me.. -Mr X. hated him- and we grew closer.. and my feelings started developing towards him while the feelings for mr.X were slowly fading.. even my physical attachment had "worn out".. and so I started seeing mr.T more and more often and eventually we got together (physically) he makes me happy at least he respects me and makes me feel like a "princess".. but its kind of a hidden relationship I haven't told mr.X (of course not hed kill me) but I've been working for the last month on being more and more distant.. and I told him I loved him a lot less (mr.X) and that he has to get used to the idea that I may be going out with other guys.. he wasn't very "fond" of my decisions and we stopped talking..
up until 2 weeks ago I saw him spending all his time with another girl.. and I found out that they talked 24h but he told everyone that he considered her as a sister and wasn't ready to get in another relationship.. I could see him really happy with her and when I asked him about her he told me she reminded him a lot of me etc.. And how he has so much fun with her.. never had I seen him so happy..
now this is where I start to feel jealous and start regreetting my decisions.. I used to say our differences were irreparable (some still are) but now I realise he's changed a lot (positively).. but in the same time I'm really happy with mr.T.. And mr.X has stopped talking to me like before.. I thought this is what I wanted when we broke up but seeing him move on with this "sister" of his just makes my heart ache I mean we've been together for what.. 3years I can't help but feel really lost when I'm not with him.. he loved me so much and I rejected him... he was one of those persons that always wanted what was best for you and that wasn't enough for me.. I know I'm not supposed to compare but.. ARGH its so hard.. he was my "home" my everything my family and putting all differences aside I can't imagine myself without him taking part in my life.. and I can't pressure mr.T into being mr.X its just not fair.. I act with T like I used to do with X but I'm always deceived... at the same time I just don't want to go back with X but I can't seem to let him go to try and make the relationship with T work and maybe I don't.. what should I do??
p.s: mr.X is hurting -because he knows I "have a thing" fot T but can't seem to understand I'm not over him- and that KILLS me I feel so bad he doesn't deserve it.. and I call him from time to time but he doesn't seem to want to talk..

Help..

You've loved X for 3 years then you abandoned him because you wanted change (I sure hope there was a lot of communication during this time). Now you see that he's happy again and you can't stand it.

You can not have the best of both worlds, you are being extremely selfish. X appears to have moved on so please don't interfere with his life now (go NC or you'll just keep giving him false hope). He finally found a way to regain his composure and claw his way back to a decent state, so if you wanted the best for him, let him go. As for T, he really doesn't deserve your emotional infidelity. Your not even over your ex and you've jumped into another relationship. I know this makes it easier for you by replacing X with T but in the end, it's unhealthy for you. Your just temporarily filling the void with a band-aid approach. If you truly loved T for T, you would not be making any comparison between him and X.

My advice would be to stay single for now. You feel lost without X so now you need to truly find yourself. You don't need to be in a relationship to be happy, you must find happiness from within. Take some time alone and learn more about yourself so you can grow from this experience. Don't rush anything or you may ultimately, regret it. Good luck.

Wow. I think you are just jealous because he found someone else. You two (Mr x and u) have not worked on any of the problem you two had, so going back out with will create the same old problems.Go nc with MR x and don't date Mr t, it will just be a rebound relationship.
Good Luck

Stay single and leave them both alone.

For all that long drama you posted, the main thing is your not ready for an exclusive relationship, because you still are living in the past.