>risk the chance of ending our relationship
This really only happens to weak friendships. If you're truly her friend, and if she rejects you, you'll be a man about it and still be her friend afterwards without being all awkward about it. If you can confidently say you truly are her friend, then go for it - you can only win. Either she says yes [yay!], or you finally get rid of your crush on her and can pursue another girl with no hangups.