Sister in law drama

Ok so I been with my boyfriend for almost 3yrs I am pregnant due anyday now , he has 2 kids with he’s ex that I have no problems with at all. i talked to her and told her the kids are more then welcome to come over when ever, the problem with my sister in law is that her and her bf are always fighting I offered her to come and stay here with us I been nothing but nice to her, so she finally broke up with hem so instead of her coming to stay with us she choices to stay with my boyfriends ex I’m i wrong for feeling disrespected by her and mad at my boyfriend for not telling her anything???