If you really loved her, you wouldn't try to break her relationship
with her boyfriend, because you'd want to see her happy. Be there
for her when she needs you, but don't say anything bad about her
boyfriend especially when the two of them are having a rough patch.
After all, if they get back together, don't you think she'd put her
boyfriend in first priority? the best advice I can offer you is to
remain friends with her while looking for other girls, because you
don't want to waste your time trying to get with a girl who is in
love with someone else. After all, you only live
once<3