Figuring the unfigurable : Romantic Love

What is romantic love that lasts a lifetime.... at its core?

I think the only kind of love that lasts is when both people make a choice to love each other every single day for the remainder of their lives.
This isn't to say they'll be agreeable with each other, that they'll not notice and admire other people, that they'll not fall out of the feelings of "love/lust".
It just means, despite what happened in the past, in my mind a day ago, a month ago, or even years ago, I wake up and choose to love the person today. Not for their past, or future, just today.
That promise, that every morning I will choose to love you anew for that day, that promise if sacrosanct, is I believe the core essence of long lasting love. Imagine being so NOT fickle, so reliable, so dependable, so sure, so stubborn, so disciplined to make that choice. Not one, but two people! Every single day. For life!

What is more difficult in the romantic aspect? Conditional or unconditional love?

While I love to love a LOT.... ( I love people, so it's really easy for me to love anyone <3. One of my exes had asked me, "How is your love for me any different than your love for your friends?
You're the same with everyone. You share your life and mind and emotions and thoughts and beliefs. You don’t really keep secrets. You do the same activities with anyone you want to. You share physical spaces with guys and girls alike (It was normal in our university to hang out together), not differentiating between them. You don't even think of them differently"
He'd been thinking about it and been very confused for a while. I'd been thrown by that question and I knew he was right. Except for the physical nature of my relationship, I was/am the same with everyone.
I think I didn't know the answer then, that I had chosen to romantically love him and not anyone else. That a large part of my mind and heart were occupied by him and I felt everything so deeply. That my highest time and effort was given to him, even over myself. Everyone else came after that, including my work. And I'd never questioned that choice)....
It's not been easy. I have hurt and got hurt in it. I have crossed boundaries and mine have been crossed too. I've grieved, suffered needlessly. I've felt lows so deeply, as deep as my highs.
I do differentiate between men and women. He meant it spiritually :p
And reader, I do keep secrets, so deep within me. I don’t wish to bleed from the depth of them, from their pain, shame, loneliness. A few people in my life are privy to some of them

I believe conditional love is mostly what I've known, the way I've loved and the love I've experienced all my life in relationships. (You guessed that right, learnt a bit of that from dad dearest.) Conditions laid out by me or the other party. Conditions of trust, communication, behaviour expectations. Even then, love is tough to last for years. The longest relationship I was in was 6 years, but it didn't last.
Only loves that come close to unconditional love are my mother's, my sister's, my grandparents' and a few of my close friends (Shoutout). My love towards strangers, colleagues and friends falls in that category too. I just love them, and wish the best for them, no matter who they are, what they do, how they behave. It's easier to do that as they don't come back home with me (pun intended)
I've known one romantic love that came close to unconditional on most days. But the conditions that were broken were those of trust, communication. Alas.
If I was capable of unconditional love, I think all of my relationships would have lasted.
The only love that's truly unconditional is my love towards myself. I love myself daily, no matter what or who I am. It's a choice :) It's also a chore! It took me so many years of reflection and therapy to reach here.
It's not easy either. So, I wonder which one would be easier in reality. Conditional or unconditional romantic love.

How is unconditional love possible? Is it even possible?

People say love towards dogs or cats is unconditional love. That an animal's love towards people is unconditional. I vehemently disagree. Such extremely controlled environments!!!
They don't speak, they don't have human expectations from us - if they do, how would we even know...., they don't have identities, conflicts, turmoils, disagreements with us. They have no choice but to accept the love and care we give. Sure, they could bite or run away, but the ones that don't, they've accepted the conditions.
For humans to be able to love unconditionally, I think, requires immense self belief. Immense self acceptance. Unconditional trust towards others. Trust that they'll behave a certain way, and trust that they'll never behave a certain way. Trust that if the behaviour changes, you'll adapt and be totally okay ;) :D
Immense capability for true understanding, forgiveness, starting anew daily, having no expectations from the past or for the future. No matter what the other person says, does or thinks at any time, the comfort and confidence of knowing that it's not your responsibility or lookout. Your only responsibility is towards yourself, your thoughts, your behaviours, your emotions. The rest isn't in your control.
Funnily, I think the more you unconditionally love yourself, the easier unconditional love towards others is.
Ironically, in reality, I realised, that's not what people (romantic and platonic) wanted out of me when I showed that kind of love. They put conditions when I became unconditional at loving them :) Funny, and yet, not fun. But then, that's not on me. I'll still be here, loving them unconditionally from afar, wanting the very best for them, thanking them (and even sometimes, loving them) in my memories and in present thoughts.
Anyway, this is all I had to share. For now.