Well I had a long reply all set to post then the cat stepped on the keyboard.

The short of it is that your feelings are normal. BUT when you truly love someone, their happiness is the most important thing. If they find happiness with a mate then that overcomes the rest. If you were to act as you say you think you will, remember that it's your brother that would be hurt. When you love someone, you do whatever you can to keep them from pain.

My youngest son is married. I truly do love his wife. I didn't think I ever would. But the fact is, he's in love, she loves him and he's happiest with her. I don't have to live with her, he does. This is his choice to make and he's made it. In the end, my love for him far out weighs my dislike of his mate.

I dislike my brother's wife very much. I've never liked her. Ironically the things my brother dislikes about my daughter-in-law are the very things I cannot stand in his own wife. But again, you have a choice, lose your brother and damage that relationship forever or accept the things you cannot change. Love always wins in the end.