[[ Yes, he would. As much as I love Itasasu, Itachi would be an obstacle to it. There are several reasons for this.
1) They are blood brothers.
2) They are both men.
3) Even if Itachi came to terms with #1 and #2, the most important thing is he doesn’t feel worthy of being in a relationship with Sasuke. He’s hurt him too much, and it’s likely he’ll hurt him again. He would much rather Sasuke find someone else– someone else who hasn’t hurt him in the way Itachi did. All of these apply even if Itachi shares the feelings Sasuke does. He just ultimately doesn’t think he’s the right person for him.
Mind you, a rejection likely wouldn’t be enough to halt Sasuke. If he’s determined, he’ll keep pushing. With enough pushing, Itachi will eventually relent. Sure, it’s going to be difficult for him to get past the “not worthy” thing, but if it makes Sasuke happy, he will give in. ]]