Some "Trinitrians" are actually Tritheists in disguise.
They do not comprehend the Oneness between Father, Son, and Holy Ghost and so they actually think of the three as being separate rather than distinct. They say it is the Trinity but in their hearts they are worshipping three "people" who are God...Tritheism.
To have the proper Trinity you must accept that God is one Person who also exists distinctly as three individuals within the Godhead.
You must understand that the Trinity itself is a statement of paradox...although it can be understood if you simply accept all of the scriptures that speak on the subject.
One of the primary scriptures is the scripture that says that the name of the Son will be called among other things
the everlasting Father.
If you do not take that scripture at face value you will very likely diverge into Tritheism in your understanding.
For it teaches that it was the Father (not an eternally begotten Son) who descended to become a Man in the incarnation.
It teaches that Jesus was begotten in the incarnation; and that when He rose again, He rose again to full all things...to inhabit eternity once again.
The Father, who inhabiteth eternity, descended to become the Son;
Eph 3:11, According to the eternal purpose which he purposed in Christ Jesus our Lord:
He did not
vacate eternity when He descended.
Therefore there is the Father in heaven and the Son on earth.
Can you see how these are the same Person and yet there is a distinction between the two?