At what point do you decide a friendship isn't worth it?

Here’s the deal. I have a friend from college (who was my best friend), and we were very close for years. A year ago, I broke up with my very long term boyfriend (we were all good friends), and I started dating another guy. She doesn’t like him because he knows my ex, and had personal beef about the whole situation. Flash forward a year: I am still with this guy, and I love him very much. In fact, we will probably get married. My friendship with this person is strained, and hasn’t been the same since. I don’t understand why she can’t be happy I am with a wonderful person who cares about me, and that I am happy. That is all I want for my friends and family! Anyhow, we were able to move past our differences, but she honestly pretends that my relationship doesn’t exist. I am sick of pretending a gigantic, positive part of my life doesn’t exist because it makes her feel uncomfortable (note: she is the only person in my life that feels this way). So I ask this. Do you keep a friendship with someone who acts like this? I feel like it is very juvenile to behave this way, but I also believe in respecting someone else’s opinion. Help?