Am I really wrong ???
The situation you're in is truly heartbreaking. No one but you can decide for yourself if you're right or wrong. However, other people can share their experiences and beliefs.
One question that comes to mind is, would you feel the same exact way if the other person were a male? In other words, if she didn't come out as gay and flaunt it on Facebook, would you still be reacting the same way?
If the answer is to any degree no, then I do think you're making a big mistake in not accepting your daughter's homosexuality. If you've been outspoken about disapproving of gays in the past, is it any wonder that she didn't come out to you, and that part of her coming out is associated with a rejection of you? Her flaunting it on FB might be really empowering for her.
My second question is about your boundary setting. Boundaries are necessary for healthy relationships, but there are some boundaries that are not healthy. A boundary that most people can recognize as reasonable and healthy is
You may not physically strike me or verbally abuse me. If you do, I will be forced to protect myself by separating myself from you, and, if you do not seek treatment, ending the relationship.
An unhealthy boundary is
I expect you to know what I'm feeling at all times. If you don't, then you can't be in my life.
These are extremes, of course, but a lot of people don't have good middle-ground boundaries.
Another bad boundary is
If you don't obey me, I can't continue to be in relationship with you.
This is an attempt to control a person. You can't control other people. That's an illusion.
A valid boundary is
To watch this person abuse you is very painful to me. You cannot ask me to watch this. Therefore I will only see you at times this person is not with you. That can be at my house or in public, or at your house if there is no criminal activity going on and that person is not there.
But an equally valid boundary is
If you cannot be courteous the person I love, and who is the most important person in my life right now, I cannot expose them to you, and if you cannot refrain from speaking discourteously to me about the person I love, we cannot speak to each other.
Boundaries can be painful for the people on either side. If you love someone and value your relationship with them, you will set your boundaries carefully and respectfully, and you will honor them, so that trust can be built, trust being a vital part of a good relationship.
If you're having difficulty with setting good boundaries, a counselor might be able to help you sort through these difficult issues and help you see where you should draw your boundaries. You may find something that you're much happier with than what you have in place right now. until then, please be aware that words, like arrows, can't be called back once they've been launched. Saying less when you are upset is usually better than saying more.
I hope you find a middle ground here where you and your daughter both feel respected and loved.
10 Ways to Build and Preserve Better Boundaries
Setting Boundaries With Parents After You Get Married This might help you to see things from your daughter's perspective.