My boyfriend did not introduce to his family for the first year we were together. He is weird to me about some things, like for example he still lives with his mom in the house he grew up in. Nothing is wrong with that.

Really? And there are many other things? Like what?

When you say "still" lives with his mother, do you mean he has never lived on his own before?

Is there something in particular that is making you think about giving up or just too much weirdness in general?

My DH lived with his mom when we first started seeing each other, he was in his 40's. He hadn't always lived there, but his stepdad is an alcoholic and I think his mom liked having DH there sorta as a barrier/protector. So depending on the circumstances I might could over look him living with his mom. But now him not introducing me to his family for a year that would be a big red flag to me. I mean why not? He ashamed of you? These are questions I would need answers too.

The change in his son could be that he sees since you have been around a while that you are not a fleeting moment and he is afraid you won't go away so he can have dad to himself like he has always had.

I know I don't know the whole story but i'm going to say this from experience, you are 41, if you don't feel it's right and you are having red flags I would move on. I'm 51, have been with my DH for six years now, I promise you I had red flags the first three years of our relationship and I married him anyway, 3 months after we got married his daughter moved in with us, if I had not signed those papers I would be gone. Those red flags we feel in our gut are usually there for a reason.

Follow your instincts. I think you know the right answer. No one has the right to be mean to you. You don't need someone who mistreats you in your life. Anger issues? You've been together 1.5 years? I would high tail it out of there. I married a man with anger issues; my exH. He beat my ass twice and that was enough for me. I'm not saying everyone with anger issues behaves like this. Heck, I've got anger issues too. I'm working on it but it is something to pay attention to.
Please love yourself enough to see the writing on the wall. Life is too short to waste on someone who is raising these red flags in your mind after 1.5 years of dating. I wasted 6 years of my life with my 1st husband. I finally got out, met my DH and found someone who values me and loves me and my kids.
Maybe you should take some time to be alone and think about why you want to be in this relationship. I wish you luck. Take care

Do you want to still be in this relationship in 5 years time? There are a number of red flags here that I have experienced in previous relationships and I am glad that I have moved on from them. The one that I've experienced before is having a bad temper. With my ex it did get less frequent over time but it was still there and at times it was pretty scary or just frustrating to have to deal with temper tantrums from a grown man. He also lived at home longer than is usual (into late 20's for him) and was coddled by his parents. He had just moved out when I met him and had a lot to learn about being mature. I met him when I was 21 and it was tough going out with an older guy who acted somewhere between a toddler and a teenager. I can't imagine living with that in my 40's. Also, I would consider how much of the parenting his mother does with the grandson, and ask yourself if your boyfriend would expect you to take on her role if you two were to ever move in together. You would also have the grandmother critiquing your parenting skills in addition to the boy's birth mother, is that worth dealing with?

TBH from what you have written it sounds like you are unhappy in this relationship and want someone to tell you that you should leave. Trust yourself and your gut. You know there are lots of things wrong with this situation. Sure there are probably some positives but do they really outweigh the negatives? I'm sure that you could find a much better man than him or simply have a much easier life being single and not having to deal with his temper and baggage.

In the short term as for the SS questioning everything you say you need to mention it to your boyfriend and tell him that you are fed up with it and that you expect it to stop as it is disrespectful. Kids should not answer back at adults and comparing people to others all the time is rude. If SS starts to question you. Just tell him "I am right and I will not argue with you" then refuse to engage with him until he stops trying to argue with you. Your boyfriend should back you up if SS continues. If he doesn't back you up take that as yet another red flag that he won't insist that his son respects you and is unlikely to do so in the future and ask yourself if you can live with that going forward.