My sister’s husband hit on me!!! 😡😡😡

I’m going to post this anonymously because my sister is also on this app for her new baby.

My sister had a baby few months ago so I have been spending a lot of time at her house helping her with my nephew. One Saturday afternoon, my sister went out and I stayed with baby. I wasn’t expecting her husband to come back, but he did. We were goood and conversed as normal, after all he has been my brother in law for three years. I excused myself and went to change my nephew, next thing was I felt a hand across my bottom. I nearly passed out of shock!!!! In front of his own child! I asked him what he was doing and he said “you are dressed in those shorts in my house and you are asking me what I’m doing. I’m attracted to you”. Oh then I told him off badly, dressed up my nephew and I left the house. I texted my sister that I urgently had somewhere to go to. I couldn’t bring myself to telling her what her sorry excuse of a husband did. Since then I haven’t visited them and my sister keeps asking me to babysit. I feel bad always having to make excuses but I really don’t know how I can tell her what happened. She’s already going through mild Postpartum depression... I don’t want to make it worst. I don’t know how to handle this situation right now but I’ll just stay away until I do. I am still in shock. I’ve had to remove some information so as not to obviously expose myself,,,, ugh I don’t want to see my sister hurt!