Do you believe when a man says he is loving 2 person at the same time?

Yes, I believe it. It IS possible. But although he may love them equally, he likely doesn't love them the same.
How do I know? I lived it.
My husband dated my best friend before we got together; he was still dating her when we fell in love. They had problems in their relationship, but even still it made us both miserable. She had done nothing wrong, nothing to deserve this, and neither of us could bear to hurt her. He loved her every bit as much as he loved me, but differently. He would always care for her, be protective of her, and a part of him at the time was still romantically connected to her. But in the end, his desire to protect her and not hurt her did not outweigh his desire to be with me. It was a long road for him to get there, though - two or three months, I believe, which at our age was quite a long time.
So yes, it is entirely possible, and he will figure out which one means more to him romantically at some point - hopefully before it's too late.

As a side note, my best friend fully recovered from the betrayal, and was a maid of honor at our wedding - I was her matron of honor when she got married.

I am a man and I can't love two person at the same time. I can't serve to persons at the same time. My heart should only belong to one. Life is so simple why should your friend make it complicated. We only have one heart not 2.Maybe I could say I like the other company but not love, I could be attracted to her but not more then that. Love is not hurting or causing pains and doubts.Maybe the other one is lust and the other one is his serious about it. O r his not satisfied with the other one. In the end he will only choose one. Have a nice day!