"Blood is thicker than water", "Friends don't let friends...", "Until death do us part", and a small flurry of other 'no matter what you do' sayings that define how permanent many relationships are. But, they are faulty; because there is separation, there is division, there is abandonment in this world. Somehow, somewhere, sometime, there is something you will do, or something someone will do to you that will cause you to distance yourself... for good or bad, we all experience 'conditional love' and brokenness in our lives. Unfortunately, it sets the stage for distrust toward God, too.
Jesus told us many times He'd never leave us nor forsake us, God even showed the Israelites He always be with them in their Tabernacle while they 'wandered'. Oddly, we tend to distance ourselves from Him... and Psalms 89:15-16 reminds us; "Blessed is the people that know the joyful sound: they shall walk, O Lord, in the light of thy countenance. (16) In thy name shall they rejoice all the day: and in thy righteousness shall they be exalted." His presence in our lives is much more than some fancy charm, a spiritual/emotional crutch, or even on an 'as needed' basis. You may not feel it, may not nurture it, or may not trust Him enough to realize it. You do not have to experience some colossal event to be face-to-face with Him.
He will never let you go. Feeling lonely for Him, or losing that sense of contact, or even just experiencing silence from Him has often caused us to lose interest, or feel rejected (again), and maybe even unworthy (some sin/disobedience in your life). While these 'things' have been the cause for others to abandon you or push you away, the Lord is right there 'under your breath', right there in your whispered prayers, right there in your heart and soul. Jude 1:24-25 even states; "Now unto him that is able to keep you from falling, and to present you faultless before the presence of his glory with exceeding joy, (25) To the only wise God our Saviour, be glory and majesty, dominion and power, both now and ever. Amen.", which is confirmation just how patient, loving, and accepting His mercy is for your life... you'll wander, you'll flounder, but He won't make you go away!
How to know?
Take Him at His word! Psalms 41:12 iterates it with; "And as for me, thou upholdest me in mine integrity, and settest me before thy face for ever.", which is to say that He is right there for you... nurturing you spirit, challenging your Faith Walk (bigger, better steps), and face-to-face with your journey. While you do 'go', you don't go away from Him. You may hide, you may run, you may even purposely avoid Him, but there you don't go; away from His forgiveness, His love, His restoration.