I was in this situation. I always wanted kids, but he didn’t, and he’d had a vasectomy before we met. We fell head over heels in love, best relationship either of us had ever had, we had a great relationship - so he said he could see himself having kids with me, and he’d get the vasectomy reversed.
We got engaged and bought a house together. He booked a private appointment to discuss the reversal, but it clashed with a last minute holiday so he cancelled it. And then somehow it never got rebooked, he always had a reason why he hadn’t called.
In my heart of hearts I knew the answer, I knew he didn’t want kids. But in every other way our lives we’re so perfect. But I was early 30s, and I knew time was passing and I had to make a decision.
Like you I agonised over never meeting anyone else - leaving my lovely partner because I wanted children, only to not meet anyone else, and to end up losing both partner and possibility of kids. So in the end, after confronting him and ascertaining that he definitely didn’t want kids, I left and did it on my own using sperm donation. I now have 2 kids ages 15 and 11, and I have a (non resident) partner who I’ve been with for 4 years. I have no regrets.
The turning point for me came one Sunday when I was with my ex. He’d been out on his bike, and was reading the paper, and looked as happy and fulfilled as anyone could ever be. I realised that this was what he wanted, for ever, and I knew it wouldn’t be enough for me. I felt a tiny twinge of resentment that he was happy and I was in turmoil, and I knew that the resentment would grow and destroy our relationship anyway.
Good luck OP, it’s a horrible situation to be in. But of course you may be fine, he may happily have kids with you, one way or another. You need to have the conversation.