Elena was supposed to be his true love

Elena was only 17 when she and Stefan were together. Not your usual age for engagement

Stefan probably will always love Elena , but Elena will always love Damon more .

Should Stefan just spent the rest of very long life alone , because he loves Elena more than she loves him .

And the Traveler magic spell which make the Silas doppelgangers and Amara doppelgangers search for each together .The Spell is gone , and some of their feeling to each other are gone as well .

how much Stefan's love for Elena was cause by the Spell.
Both Elena and Stefan are unsure it themselves.

Well, Elena and Stefan were a bit too young and early in their relationship to get married. It was a teen fantasy drama at the time, after all.
But honestly, Steroline is happening way too fast by that standard. Delena would make sense, Jo/Alaric did too (as they were both older, wanted kids/to settle down), and if Stelena were still together..they would too. But Steroline have only been dating for like, a few months? Idk. Makes no sense to me, why not slow down? I feel like Bonnie and Enzo have been dating for even longer than thse two because they were together during that three year time jump.

A rose is just a rose.

You're ignoring the years of development between Stefan and Caroline BEFORE they got together. I don't understand people's reasoning when speaking about the proposal.
They've been friends since season two, growing closer with each season to the point where Stefan calls her his best friend and the person he can "be himself and cry with" and the person he once attempted to hide his shame from because he didn't want her "to think less of him". These were direct quotes and events that took place before season 7.

Season 6 he said he liked her. Season 7 he said he loved her. 3 years later he still loves her, and so does she. So that's what, like 8 years of development? And like a year or some months between him saying I like you and I love you. Yet Elena and Stefan got together in ep 2 and said I love you in the same season? So I'm honestly confused when people say they think the relationship is going too fast when there's time and evidence shown in the show that contradicts this.

And I don't think Stefan proposed to Caroline bc he was "losing Damon and his family". He proposed to her IN SPITE of it. Stefan and Caroline have always had bad timing when it came to their relationship. Caroline's mother died and she turned her switch off. The heretics came and fcked them over season 7, and now Damon is taken over by Sybil and Sarah died. Sh7t is always hitting the fan. Which was why Stefan said to her mother in S6 that he's waiting for the "perfect" time to be with Caroline.

This proposal showed that Stefan doesn't need everything to be perfect in order to love and be happy with Caroline. He's always been worrying about the moment and his brother, and finally he shows he is now willing to accept and embrace his happiness whenever he can. That's why he proposed to Caroline despite all the chaos that's been happening. He accepted the situation for what it was and was still willing to move on with his life.

So no, I don't think the proposal was out of place, nor do I think that Stefan was trying to rush it or that Stefan is still "in love with Elena" and is trying to compensate for it. If he was he would have went for her and married her a long time ago, not wait for her for 3 freaking years and accept her kids as his own.