Struggling with Relationship Issues: Need Advice

I’m struggling a lot rn. Some context, my boyfriend and I have been together for 3.5 years. We allow each other to go thru one another’s phone occasionally for reassurance and stuff. I have always had a suspicion that his mom didn’t like me. Tonight I went thru to check for some stuff that we agreed neither of us would have and saw text messages from his mom calling me dirty and untrustworthy and stuff. We recently went on a family vacation with his family to Alabama and she didn’t want me to go. I feel like he is being pulled between two people and I don’t want that for him. I feel like I need to break up with him before we get any farther into our relationship. I adore him but I do not see anything getting better with stuff like this. We were both just raised so differently. Please help.