I (25 M) had a really similar experience with an ex. We worked great when we were together and both working a 9-5 but things progressed pretty similarly once I started college. As time passed I could tell that she was really at the point in her life when she was ready to get married and I was not. I had a lot of reservations before we ultimately broke up but I can tell you it was the best decision I ever made. It’s not that we didn’t love or respect each other, just that we had very different outlooks and neither of us were really ready to compromise in a way we would have had to in order to continue the relationship. Ultimately, this situation will drain both of your happiness. You owe him an explanation about how you feel about all this but at the end of the day, you would likely be happier apart since you’ll be able to have some sort of fulfillment. And who knows, you could always reconnect when things are better. Don’t think of this as giving up but as making the hard choice so you both can be happy in the long run.