FWB situation is ending bc they met someone else, why do i feel sad

26F was FWB with 23M for the last 3 months. We met on tinder, hooked up once, and snapped back n forth for a few weeks after. We were both casually seeing other people and hooking up with others during this time, and then in June we started to hook up on a consistent basis. We would drink, have sex, talk about life. We agreed one night that we would be FWB until the other person found the love of their life. He told me he always blocks girls after hooking up with them, but it was different with me for some reason idk. And there is one other guy i see every now and then too.
Anyway i was going over to his place 2-3x a week, texting all day every day, sometimes i would just go over to there to watch him play video games, watch a movie, eat taco bell, etc. Then i left for a trip out of town, and i noticed he didnt open my snap for like 10hours (very unlike him)….brushed it off at first but then he did the same thing the next day.
I get back from my trip and we had been talkin throughout the day, talking about football, etc etc….and asked him if he wanted to hang out.
He said “No its complicated.”
I said “You ok?”
He said “Ya”
I said “Alright well lmk if u need to talk”
He said “Will do for sure”
I said “Bet i’ll give ya space”
Then we didnt talk for a couple days, and i said “You still doin ok dude?”
He said “Yea im talking to somebody rn homie”
And i told him i wish he wouldve just told me, bc im happy for him! And that i will leave him be and keep my distance.
He said “Thanks homie”
And i left it at that, didnt respond bc i want him to know i respect it, and i dont want to overstep. Mainly because i fuckin love our friendship, and dont wanna lose him altogether. We’ve bonded a lot over the last couple months!
Anyway, i dont know why i feel so sad about it all. I think im just afraid to lose a friend. I hope that doesnt happen, but i do want him to be happy. Just weird feelings. This was my first true fwb situation too, so maybe thats why im a little more attached to it.
Any song suggestions for moving on from a FWB ending? Lol. I process best with music.

TL;DR! FWB situation of 3 months ended because he’s talking to somebody new, and im happy for him but feeling sad about the loss of friendship. Advice and songs for moving on are encouraged.