mourning a relationship that hasn't technically ended yet

hey y'all. this is my first time posting in this subreddit because this is the first time i've truly been head over heals for someone i've dated, but i really need some advice.

i (22F) met this guy two years ago and was honestly instantly attracted to him. i was dating someone else at the time and the main reason i ended up breaking up with him a couple of months later was because i realized the guy i was already dating for six months never made me feel the same way this guy did. we were both dealing with shit but he was perfect in my eyes. same degree, same music taste, same values. i have never been as attracted to anyone physically as i am to him either. i could go on and on but you get the point. he had expressed attraction to me at the time too but backed off because i was still taken.

long story short we lost touch for a few months because i went through a manic episode and needed to recuperate. a little less than two months ago i reached out to him because he was on my mind, just hoping to at least rekindle a friendship. well we ended up going on a date and vibed so well we decided to kinda make things official. that date was the most at peace i've been in a really long time and the month we've been official has been one of the most stable periods of my life. i feel comfortable around him in ways i've never felt around anyone else. i think about him 24/7 and have thought about doing things for him i'd never even consider doing for anyone else.

fast forward to this past Saturday, vibe was hella off when we went out. i had noticed this for a few days but any time i asked if everything was okay or if i did something wrong, it was dismissed. the next day we had a chat and he said he wanted to take a step back to rethink things. i think this is very fair considering both of our financial situations + the distance, bit of an age gap, both of our mental health issues and some personal stuff he has going on. honestly we took things way too fast after saying we wanted to take things slow, but now i'm in a dilemma.

i have had a ton of traumatic dating + sexual experiences and this is the first guy i have felt completely safe around. this is the first guy i have even looked at and said "forever may be cool with him,"let alone committed so quickly. we have a trip planned for next week and it's still on as of now but i have feeling that may be the last time we see each other and my heart is shattered. i'm 99% sure the only reason he isn't canceling is to avoid hurting my feelings. we're taking space but i can tell a lot of the attraction is gone and he's realizing it was a mistake to ask me out.

my question is, how do i prepare for this to end? i have broken things off with a lot of people, but this is the first time i really hoped it would work out. the instant switch between him idealizing me and seeming completely indifferent around me is already so painful, and i feel like such an idiot for thinking someone could genuinely care about me this much. my life has been horrible the past year and i felt like things were finally looking up when we got together. i've been really depressed since we had our chat and don't want to tell him that because it may come off as manipulative. i want him to thrive and would still care about him tremendously if this is something he needs to end for his own good. at the same time, i know i won't be okay when we officially break things off. i can't even imagine dating anyone else after the way he's made me feel. what should i do?