I would like to ask as many others have: Why are you moving so fast? You are in the earliest phase of your relationship(s) and are not only talking about children but already in practical realization of them? I mean, it is always good to discuss all topics that are out there and plan when they may become relevant for you, my men and I are doing that as well, even though we are not a year in the mix already, but I would feel just like you, this is way too fast to actually start trying to get pregnant after only three months time.
My husband and I planned to have our first child next year. Fortunately my boyfriend is on the same page (wants children in our relationship) and adjusting to the thought of having non-biological children around and wants to have a biological one in some years as well. But this took longer to discuss and talk about purely theoretically than the time you three have been together up to now. And I think it is safe to say that we are already moving fast there. Of course, relationships shouldn't be compared, but I recommend slowing down instantly and start the talking, with all three of you involved.
Even if you feel uncomfortable pressing the topic that is an urgent one for you, stand up for what you think and wish for and get them at a table to talk about what everyone has in mind when thinking about the future of your relationship. If you don't tell them that you have got the feeling that some important parts of their communication and planning involves you as well and that they seem to not see that and exclude you from the decision making process, you won't stop worrying and feeling treated unfair. As others have said, your husband has no right in this situation to get angry with you. This sounds like serious NRE and maybe he needs you to show him how unreasonable he is acting right now.
As I already mentioned, I myself am not in the best situation to talk about going slow, we moved my boyfriend in as soon as possible, we talk about the possibility of children after being together for roughly seven months and so on. But what we never did up to now is making decisions without involving all three of us. Each development in one relationship effects all others that are around this one and therefore all persons involved need to be on the same page. You need to get that clear and work on that, as couples and as a triad.
Facts: 30, female, bi, v-type relationship with Sward (husband, straight, mono) and Lin (boyfriend, straight, mono), poly-fi and co-primary.