Step Dad, causing me stress

I am 31 and 6 months pregnant with my first. My husband and I traveled to visit my Mom and Step Dad who decided to be "snow birds" for the first time this year. We thought it would be a great time to get away from the snow and spend family time before baby comes.

We flew out there and spent 4 nights with them in their rental house. Per their request since they had so much space. All it did was cause me so much anxiety.

They have been married for 10 years and my Step Dad and I really do not have any sort of relationship. The whole time he kept saying things like I want to move here permanently. Which would mean they would live half a country away from their 5 children and 11 grandchildren. My mom seemed so lonely there. She was just craving someone to talk to.

Late one evening after my husband and parents had a few drinks we were watching tv. I made a comment about what we were watching and my step dad disagreed. Totally fine. My husband thinking this was a normal conversation chimes in. I stop him and let it be. That night my parents get into a fight and one of them ends up sleeping on a lawn chair.

This whole situation makes me horribly uncomfortable. I get blamed the next morning for their fight. I seriously cannot make this up. We are all adults with college educations and I this drama is ridiculous. My step dad apologizes and also calls me an idiot. This is beyond NOT ok by me. My mom confesses during this "family chat" that my step dad doesn't let her have an opinion and she gets heated by it due to her pass abuse from my dad.

This is only day 2 of our vacation together. My mom is in tears because she feels as though her family is not going to get along. So I make amends with my step dad for her sake and only her sake. The whole trip she kept apologizing for him. Really made me so sad.

My mom spent years in a marriage with a verbal abuser. She had no voice. Now she's in a marriage where she is never allowed to speak about her beliefs, wants, needs. My heart just aches for her sadness. I know their fight had nothing to do with me and everything to do what has been building up in their marriage.

It has been 4 days since we flew back home. I honestly want nothing to do with him. My husband understands. We just so love my mom and they are a package deal. This isn't the first time something like this has happened. I don't like being the cause of someone's marriage problems. I also don't like being constantly belittled. It has been keeping me up at night and it is stressing me out. I randomly just start crying.

My husband has tried to reassure me that my feelings are ok that I am not a bad person. He is over it all. I am just not. It strikes a spot in my heart and it weighs me down.