I'm Always Trying to Understand Why

So I had a neighbor that was married, we stayed friends even after her marriage ended. We tried going out but she made it clear she did not want any more children than she has, actually had tubes tied, and she never wanted to get married again. She was clear about the no marriage with all friends and family. This was in stark contrast to what I wanted so we just remained friends... very close friends. She had an elective surgery that I did not agree with last year. Started seeing a new guy and never talking to me, but I get it... relationships are like that sometimes. Additionally it was pretty clear that he didnt like her hanging out with me even though he never met me. He would call and text multiple times if we went to a movie or dinner. She even cancelled for my moms birthday party with a bogus excuse and it was clear to me it was him controlling. Tonight she goes to Las Vegas and gets married to him. I just don't get how someone can be so opposed to marriage them on a whim elope. I guess if it's right it's right but still.