SquirrelX?

SquirrelXShrew would have been a sweet couple, too :3

Bramblestar if I had to choose, but I don't really care for Squirrelflight ships.

Also, just because Ashfur had a bad life doesn't excuse his actions. He holds grudges to the point where it's dangerous. He still conspired with Hawkfrost, indirectly made Firestar lose a life, tried to harm Lionblaze twice, tried to burn the Original Three alive, and treated to reveal Squirrelflight's secret.

Another thing, he actually used Brindleface's death as an excuse as to why Brambleclaw wasn't right for Squirrelflight just because he was Tigerstar's son. Note that the two were actually good friends at one point.

Dustpelt was actually a good mentor to Ashfur and the bad things didn't really start to happen to Dustpelt until after Ashfur became a warrior. Dustpelt isn't the type of cat to let his personal issues get in the way of his duty anyway. Let's not forget that he was also mentor to Squirrelflight, temporarily mentored Sorreltail, and mentored Hazeltail.

And yes, Brambleclaw and Squirrelflight have a complicated relationship—that's the point! Their relationship is clearly supposed to be a parallel to Firestar and Sandstorm's and any other love-hate relationship in the series or in general

And what does Whitestorm dying or him having two mates have to do with anything? Whitestorm never seemed close his kits and this was during a time where fathers weren't as attentive. Cats aren't monogamous creatures anyway and we even see this twice with Smokey and Toadskip.

Ashfur and Squirrelflight were never mates! All she wanted was a friend and Ashfur wanted more than that. Yes, she thought of taking him as a mate at least twice, but didn't want to make any decisions until she was absolutely sure of her feelings. Another thing is that Ashfur and Squirrelflight didn't go well together either—as stated twice, they were like water and fire respectively, and not in a good way like Squirrelflight and Leafpool either. He would constantly protect her, and this was something age didn't want or even need.

Ashfur also seemed to be at least slightly judgemental against kittypets when saying that Daisy and her kits didn't belong in the Clans just because they weren't born there even though his foster brother was a kittypet. This of course offends Squirrelflight since she's half kittypet and her father and Clan leader was also a kittypet.

Squirrelflight also offered to be friends with Ashfur even after she rejected him, but he kept on ignoring both her and Brambleclaw, accused Leafpool of faking a sign just because Squirrelflight chose Brambleclaw over him, and even made a subtle jibe against the pair when they were discussing ShadowClan long after Squirrelflight became mates with Brambleclaw.

I fail to see how Ashfur would've made a good mate for Squirrelflight.

I ship her with Bramblestar.

Ashfur's actions had nothing to do with his unfortunate family life. He acted out because a girl didn't like him back, which is pathetic. He stole a life from Firestar, nearly killed Lionblaze twice, and attempted to kill a blind medicine cat and a young warrior to get back at someone who never did anything wrong. Squirrelflight had every right to say no to him, regardless of how rocky her relationship with Bramblestar is. He should have just accepted she wasn't into him and moved on, but instead he tried to murder her family who had done nothing to him.

And Ashfur didn't do the same? At least Brambleclaw didn't try to kill Squirrelflight's family, he was just cold towards her and to be fair, he isn't entirely at fault. I love Squirrelflight, but she's as much at fault with her arguments with Brambleclaw as he is, and that's why their relationship suffered—miscommunication, and they always managed to make up.

Ashfur hated her the moment she rejected him and plotted on ways to make her suffer. That's not very loyal if you ask me.

It is believed Shrewpaw had a crush on her, and they were best friends.

Guys, did you forget Dustpelt was Squirrelflight's mentor too?

I pick Bramblestar. Their relationship was incredibly annoying to read when they were constantly struggling to get along with each other and arguing, but when they finally got along and got over everything, they fit each other greatly. They have history at least, and when they get along they're a pretty okay couple.