In relationship with someone while in love with someone else?

has anyone ever been in a relationship with someone but in love with someone else?
how did you cope? what did you do?

Yes I have.
The relationship inevitably didn't work out. I did a lot of comparing and weighing up and the guy i was with inevitably fell short of what I really wanted. I cared about him and wanted it to work but something was missing.
Even if I hadn't been in love with someone else at the time it still would have ended.
I should tell you though, that i didn't get the guy I was in love with either. I wasn't unfaithful to my partner while I was with him - I didn't need to be. It was just a nagging feeling that he wasn't right, he wasn't the one. I thought about the other guy the whole time. I knew that if I had been forced to make a choice, I would have chosen the other guy.
I've learned you shouldn't ignore those feelings. If you are truly in love with someone, you don't think of anyone else. It's also a little unfair on the other person you are with too.

I can't do that. I just can't. I rather tell him that I have no interest anymore that let him look like an idiot, making him think that I still love him but yet I have other picture on my mind. I just can't. I can't hurt the onbe I love. If I knew that the love is getting sour I will tell him right away.

no i haven't , but if i was in such a state , i wouldn't carry on with the guy i'm in relation with because it wouldn't be fair for both of us.

beside i believe that being in relation with someone and in love with other at the same time considers cheating. .

i would have two options: first, facing my bf that i'm in love with someone else or forget about the one i love and try to give my bf chance. beside i think it depends though i mean if that guy has the same feelings to me so yeah i would go for the first option if not then i would forget about him.