Well he would be not only does it give him power but it is now apart of him like his best friend when it joined with him it did not just attach itself to his skin but went inside and attached itself to his entire being including his mind so it was another part of him, in the comics it was stated that symbiotes took over there hosts but the Venom Symbiote wanted to belong and wanted to be apart of its host and to care for and be cared for so they sealed it away in the comics it protects Brock and cares for him it lets him web swing, stick to walls, forms cloths and he is never lonely since it is always there so if it is now apart of him since it adapts to his memories and desires if he hates Spider-Man then so does the Alien to keep him happy and to become a part of him so if he looses the Symbiote he looses his power, his friend but since it is now apart of his Mind, Heart, Skeleton, Nerves he looses apart of himself
As they have said many times they need each other to survive
Also Steve would you not be scared if you lost a Symbiote what would happen deemed insane, prison, depression