My LDR boyfriend just broke up with me and I’m confused why

My boyfriend (20M) and I (23F) had been in a LDR for 6 months, and I’m confused why he broke up with me. I have asked him for clarity but it just didn’t make sense to me.

We knew getting into a long distance relationship was hard, we had no major issues before and had constantly tried our best to communicate and be there for each other, and I felt like in the end he made up an excuse and he gave up, which is very out of character for him.

He has a very busy schedule with uni and working part time, he’s constantly saying he’s stressed with uni and work which he has re-navigated to target our relationship.

He had not mentioned any problems with me prior to going back to uni and suddenly he could not continue on with this relationship.

I have started seriously planning on visiting him this year at a time that would fit his schedule but he couldn’t wait and disregarded that.

He had told me before that he would have already proposed to me if I was there with him, I’m just so surprised that as someone he claimed to love so much be discarded so easily.

I sacrificed so much to be with him but he couldn’t be with me because of sudden stress that has nothing to do with me what so ever and took the easy way out.

I am lost and confused.