Missing: Good Friend

I hear that people don't change. I have thought that people don't change. But it begs the question; what does?
I have lost two dear friends in the past year. Now, both are female, and there were romantic feelings between us, and both got married. For the most part, things had been going fine. One stayed friends with me for years until after she got engaged, and then told me that we couldn't talk again, as it would be unfair. The other, after she got engaged, accused me of trying to break up the engagement and poison the family against the marriage. From these two, I lost nearly 20 years of friendship. So I ask again; what changed?
In both cases, our relationship changed once they had gotten deeper into the engagement. The later individual had come to me multiple times to screen boyfriends for her. I would simply ask for a name, jump on facebook, spend at most 10 minutes on their profile page and maybe wikipedia. I would then get back to her with my impressions, thoughts, and findings. She had never told me I was wrong about what I deduced, and even told me so many times how right I was. Recently, she meets a guy, and gets interested. I research. I have findings... but I don't share them. It turns out, I actually was connected to this fellow. So, I hold my findings. She gets engaged. I'm somewhat shocked. I knew this was someone that was commonly perceived as good; I had no evidence to the contrary. I just thought he was a bit over the top; grows a big beard, way too into adventure activities like mountain climbing, the whole family blogs (...don't hit me with that, okay? There's a reason my posts are so rare!). So, even though I would think that no one ever in the history of the world can possibly pass the stringent list of requirements I have for my friend, I veil my opinions from her. I don't want to interfere. However, her brother tells me how he thinks the fiance is a bit of a cheesy and weird guy. He vents to me about how he is somewhat disappointed in this relationship, because it will lead to him losing his sister. I open up to him as well, and tell him my impressions match his. The couple alerts us they will be home for a few days to meet her friends and family and have a bridal shower. A few weeks before their visit, I have an epiphany; it really doesn't matter how I think of this guy. In my eyes he might be corny, a tool, and undeserving of my friend, but standing there brushing my teeth I came to know that she loves him. He makes her supremely happy. That was all it took. I shared this with her brother, even, and he agreed with me. It didn't stop us from laughing at their near over the top texts and conversations (You know the ones. Think of facebook posts between a new couple, complete with too many hearts and pet names that don't make sense. Yeah, you laugh at that too... when you aren't cringing from it). Our making fun of his habits continued, but they were the same way we would laugh at a friend standing right with us. Unable to see my friend but for a few brief hours during her visit, I write her a heartfelt letter detailing this change that I had. When I give her the letter, I attempt to explain it all in person, with her brother there as well (who I asked if it was alright that I do this, and he thought it was a fine idea). I garble it a bit, but I'm open, honest and friendly. I hug her tightly, complete with an "I love ya!!" that she returns, and give her fiance a huge hug, too. I wish them the best, and head to work. A few days latter, I receive a message from her; she is seemingly furious at me. She states that I worked to attack and undermine a relationship that she has given her heart to, and that me saying (in the letter that I love her is duplicitous and horrid of me to do. Well I was very much so taken aback. I spent hours on that letter making sure it conveyed that I was so happy for her, that I supported her, and thought she had chosen, for herself, extremely well. I wished her happiness and joy, and gave her my complete blessing. What a mere 6 months previously was expected of me, and asked for, was now seen as immature and wicked. My wedding invitation was even revoked, and I am no longer any part of her life.
The other friend went somewhat along the same lines (friends, engaged, no more contact!). We had been friends all through high school, and she even wanted to ask me to homecoming. We dated afterwards. It didn't work out. I continued to volunteer at her church for Vacation Bible School, and we stayed friends. We dated other people. We kept in light touch, and maintained, at the least, a strong acquaintance. When I left for California as a missionary, I invited her and her family to my going away party, and her family came (she was out of state). I hugged them goodbye for 2 years... and was back 6 months later. I reached out to her, and when she was home a few weeks later, we went out for lunch, walking and talking for hours. We hadn't been with each other for a long time, and it was good to see her again. She told me all about going to grad school, and her boyfriend (they'd been dating a while at this point), and we had a good time. She got engaged over a year later, and I reached out to her (I'll admit, largely out of the blue) to ask if the wedding was in our home town, or over by her fiance's family (I was already certain I had not merited an invite to the wedding). After getting no response for a few days, I sent a text apologizing if it seemed invasive or insensitive of me to ask; I just like weddings. She called me and spent nearly 20 minutes telling me that we need to stop talking because it is unfair to her fiance. We had something (and that it would be lying if we pretended we didn't), but we need to move on. She repeated this all at least two, some of it four, times. I was hurt, but understanding. I wished her the best, and hung up.
So, two friends that I have given a piece of my heart to for since I was a measly 14 year old. Both, upon nearing their wedding days, threw me out of their lives. I had intended (previous to my emotional eviction from them) to invite both to my wedding (in the even that occurs before everyone I know is dead), even if I knew at least one friend probably wouldn't invite me to hers (we had a history... I wasn't one to pretend we hadn't had one). A year ago, I would not have foreseen this. I have been floored. I am hurt. I am not saying I am undeserving; I don't know what internal battles or struggles they have. I don't know the tone in which they read the letter or received my questions. I can't begin to perceive how they thought I felt. I was honest with them, but I feel something changed within them. Even though I have been cast aside from their life path, I do hope that they have wonderful, fulfilling, happy lives.
Please, if I am missing something here, tell me. Whether you agree or disagree with what I did and how I handled things, LET ME KNOW!!! I don't want to keep making the same mistakes.
(Written 12/15/2015)