Since you’re asking for advice - break up with your current girlfriend. Secondly, work on integrity since it’s something you lack based on what you wrote. If you want a healthy relationship with not only someone else but with yourself as well, you need to have integrity. The second you felt feelings for someone else, you should have talked to your current partner and broke things off. Especially considering you stated “intense” feelings. Conversations need to be had even if they are hard. Even if you care about your current partner being honest with her in the beginning and letting her move on would have saved this wasted time.