So my ex got engaged over the weekend ( I am already remarried and called him the day after it happened, it happened at night and told him because that means now our child has another parental role in his life)

He planned this, had his mother fly in from another state and had our son help in the engagement process of asking but now it is 3 days later and he still has not told me. I found out through my own mother from facebook. To be clear I am very happy that he found someone but I am pissed that he is all about him. This is a MAJOR change in my sons life. Now is id going to have a step mom and she has never in the past 14 months of living with them ever acted like a parental role to him and now all of the sudden bam now she is.
To me this is a big change that I believe he should of told me but nope. Am I wrong for thinking that this is a big change in my sons life and he should of at least told me because this is changing a lot with my son. People who have more authority over situations of him and more.