you ignore him would prevent him from breaking up with the current gf. You cant possibly expect him to break up with his current gf over some crush with a person who is "clearly" not interested in him??
The thing isnt about are you better than her or not. She got there first. If you want to risk being the 3rd person and being hurt a normal amount - big deal (3rd person always get that, dont think it wouldnt happen to you) then knock yourself out. Drop some hints, be closer to him
keep it simple
Self-esteem isn't bragging about how great you are. It's more like quietly knowing that you're worth a lot (priceless, in fact!). It's not about thinking you're perfect — because nobody is — but knowing that you're worthy of being loved and accepted.
"Me, I try to send this note
float it like a paper boat
But paper sinks
and words are weak
i try, but i cant speak"