It is not possible to make that determination that this has to do with "being odd" given the lack of info.
Everyone is different and has different perceptions of others, so like NG and I said, more info is needed.
I would be inclined to agree with Nursegirl, except I've seen this too often. Just last week it came around and hit me again - a dear friend I have who has 5 grown sons was disowned by her middle son. Took them COMPLETELY by surprise and hurt them to the core. You never loved me, you never supported me, you alway rejected me, etc., was what he said and it left the brothers and the parents in complete shock. I knew this boy growing up and he was kind of an effort to raise - often in trouble, didn't try in school, took 6 years to get a bachelors degree, etc. And his parents stood unwaveringly by his side.
Then he married and after several years the two of them rejected his family.
I had a cousin who had the exact same path. He's in his late 50s now and we still don't get it.
I don't think this has to do with being gay. I think it has to do with being odd. Both the young men are not successful, and I think when they look at where they are in life they think my parents must be toxic because I can't manage to get my feet under me.
I wish you well. I can't imagine the pain you are feeling, but I think it's very much coming from him and not you.
I'm sorry you're going through this.
I have to be honest, something doesn't make sense here. He's cutting off ties and calling his relationship with you "toxic", and yet you proclaim that there's nothing wrong, nothing you can think of that would make him feel that way, other than the timeline when he got married. That's really two pretty different extremes.
There's NOTHING you can think of that would make him say that? Were you always accepting of his sexuality and his partner? Do you LIKE his partner? Get along with him? Any issues there?
Really, communication is the key, but if he's closed off completely to the idea of that, there's little you can do I'm afraid. It would be helpful to have some more info to better advise you. Something just isn't adding up here....
Hang in there!
Realize that he is an adult and can't be controlled by his parent. He is free to make his own decisions, and maybe the driving force behind his decision was made by his partner. All you can do is try to get an explanation to see if there is a way to get back together, but accept his decision while doing so. Obviously that won't be easy given your feelings for him, but getting angry or anxious about it will be fruitless and will hurt you more.
Consider this burning coal example. Anger is like a burning coal thrown by one person at another. It burns both people, unless the other person ducks.