Christians, please help

My boyfriend and I have been dating for about 2.5 years. We are hoping to get engaged within the next six months. We have been having sex for as long as we’ve been together. He was my first, and he had only been with his long term girlfriend before me. Lately it’s been on my heart that we should stop having premarital sex. This feeling isn’t new, I’ve just kind of suppressed it in the past. I had always planned to be a virgin until marriage but then I met him, and that changed. I told my boyfriend I wanted to stop having sex until we are at least engaged. More than anything, I wanted him to tell me he would support me and was happy I was doing what I thought was most pleasing to God. He is a Christian too. He understood that this was important to me, but he was really sad. He has a really high sex drive and enjoys sex for the physical reasons, but also the bonding reasons. He agreed to support me, but said it would be hard for him to go without sex for months. I think I just need some encouragement. Anyone have a similar story? An encouraging word of advice? Thank you!!