[barandilwen]

i think at first he would think that it's easy to use the one ring but as his journey going back to gondor would start, he would have a hard time because the fellowship and the group of uruk-hai's are hot on his trail and when they would find boromir, he would certainly die or be cursed by the fellowship.
if he reaches gondor without any confrontation's from the fellowship and uruk-hai's, he wouldn't still have the strength to overcome the one ring because of the ring's will to go back to his master, the dark lord sauron. and then after sauron had got the ring, boromir would eventually die and middle earth would burn in the wrath of sauron.