Am I overthinking these things about my boyfriend, or are these actual red flags before marriage?

Am I overthinking these things about my boyfriend, or are these actual red flags before marriage?
My boyfriend and I have talked about getting married next summer after I finish grad school. We’re currently long distance because my program is far from where he lives. I love him and have been serious about our future, but lately I’ve noticed some patterns that are making me question whether I’m ignoring things I shouldn’t.

He has children from a previous marriage. I told him that because this would be my first marriage, I would really like the first few months of being married to just be us before immediately living full-time with his children. I wasn’t saying I don’t want them in our lives or that he shouldn’t be a father. I just wanted some time to adjust to being newly married, have privacy, and be comfortable in my own home before taking on that transition.

He took it extremely personally and made me feel guilty about even wanting that. It took multiple conversations before I felt like he actually tried to understand where I was coming from.
Another issue is how we communicate. He tends to jump to conclusions about what I mean and then gets frustrated or angry based on the conclusion he already made. When I tell him he’s misunderstanding me, sometimes it feels like I’m fighting just to get him to actually hear what I’m saying. We had one argument where he kept saying hurtful things even after I was clearly upset, and eventually I started crying, said goodbye, and hung up because I couldn’t take it anymore.

Money has also started worrying me. A few days after that argument, he told me he wouldn’t necessarily be able to provide for everything when we’re married and that we’d probably need to split bills. I understand that couples handle finances differently, but I’ve always envisioned my husband being the primary provider, especially because that’s something that’s important to me in marriage. Some of his comments also make me question whether we have the same expectations about finances.
There’s also a disconnect sexually. He rarely makes me finish, although he usually finishes himself. Sometimes he doesn’t finish either. We don’t have sex as often right now because I’m extremely busy with grad school, which I thought he understood, but sometimes I feel like he becomes emotionally distant or frustrated when we’re not as physically connected.

I don’t expect him to be perfect, and I’m trying to distinguish normal relationship problems from patterns I should seriously think about before marrying someone. What concerns me most is that lately I sometimes feel this underlying anger or resentment from him, and I don’t know whether I’m interpreting it correctly.