Marriage & Relationship Model

I am trying to work through an issue that keeps coming up in my relationship. I get offended or hurt when a friend or colleague that we work with brings up marriage or anything future related with my boyfriend- and his response is either no response (about marriage) or no no no because of this or that, as well about future related things he tends to always say “I want to do this, or I am planning that” rather than saying “we” and including me.

Now I have discussed marriage and future with him and he always tells me that of course he wants to get married to me someday and have kids and build a life together, just not now or not ready yet (which I agree with). But fear sets in when he says things that are somewhat opposite to other people. I have also spoken to him about how it makes me feel, but it keeps happening. I know this is my fears or insecurities setting in but I’m not sure where to go to change my thoughts so that I can feel excited about the present and the future rather than fearful/hurt. Please help me with a model:
C: BF says he doesn’t want marriage to others, but to me is different
T: what if he’s not being truthful with me?
F: fear, hurt, confused, insecure
A: try to talk about it – end up fighting because of insecurity/pressure/stress
R: Not having fun/nice time together- he pulls away

I would like to have thoughts of trust in my relationship and stability that my man is in love with me and wants or is stable in wanting a long term future with me. How do I work on this?