Do you have less friends as you get older?

My husband and I were talking today about this. Basically I’ve been going through a hard time as I’m losing a friend I’ve had for awhile that I was really close with. She basically had heard from a friend that my husband cheated on me and she did the right thing and told me. Very long story short, the alleged girl admitted she lied about sleeping with my husband to her friend and it hadn’t actually happened. (Multiple witnesses to attest to the fact that he did not do it) Anyway, my issue with my friend was through all this she basically had talked to me through it and told her friend and the alleged other woman everything I was saying. Which to me was a horrendous violation of trust and just a terrible thing to do. But now IM the one that’s trying to keep the friendship. She wants nothing to do with me because I called her out and told her she was wrong for doing that. Now I get ignored regularly from her and I just feel rejected. I feel like I did nothing wrong and I’m getting punished for it. My husband said that we just don’t have as many friends as we get older and have other things to focus on like families and careers. Is this true? I just feel like life is getting so much more lonely the last couple years.