Tempered glass doesnt fit at all..keeps leaving out space like this...have changed 3 until now..any idea what might be the problem..

could be it's for the iphone6+ or a defect product I would return it

Are you sure the glass is the correct version for your iPhone? iPhone 6 and iPhone 6S are slightly different.

Mine iPhone 6s is similar to yours. For iPhone 6 and iPhone 6s, the arc of each machine's edge is slightly different. However, tempered glass is made in standard size. So, it's possible that your iPhone's edge is more curved than the normal ones. Some of the tempered glass screen protectors have special design for this problem(narrower, add glue on the edge...). Have tried this one: www.haloback.com, got better.