YOU SAID:

My tree is as big as big is tree of my wife's boyfriend is

INTO JAPANESE

私のツリーは私の妻のボーイフレンドのツリーと同じくらい大きいです

BACK INTO ENGLISH

My tree is as big as my wife's boyfriend's tree

INTO JAPANESE

私の木は妻の彼氏の木と同じ大きさです

BACK INTO ENGLISH

My tree is the same size as my wife's boyfriend tree

INTO JAPANESE

私の木は妻の彼氏の木と同じサイズです

BACK INTO ENGLISH

My tree is the same size as my wife's boyfriend tree