Ok listen. I assume you're a teen bc this happened to me too when i was 16. Some girls get like that when it's their first relationship and completely ditch their friends to be with their boyfriend all the time. It isn't your fault. Friendships are not meant to be like that. Now that I'm older my friends have boyfriends but they don't ditch me for them they maintain their balance. Don't think too much about that girl. Just let it unfold. If she leaves you'll find better people who are mature and won't do the same.
You gotta communicate these things to your friend. She likely doesn't realize how you're feeling and isn't doing this intentionally. Let her know that you're happy for her! But also that you miss her. Maybe you guys can set aside some time for a weekly girls night or something. And yeah it does take getting used to. No matter how well she balances these relationships, the time she spends with you will decrease. This is an inevitable part of getting older.
Guys I need an opinion, me and my best friend are super close … but recently she went official with a guy and let’s say I already feel the difference. She told me that things aren’t going to change () Like I don’t want to hog her from him at all so I’m having her have the time ( honey moon phase) and I get it but it feels a little lonely … anyway I already lost other friends to the same situation. Also I may be feeling like this cause it’s the time of the month but it making me think that friendships are shallow and I was just a place holder until she got the guy she wanted. Idk maybe I’m over reacting … hopefully I am