You can train your heart to be open and to enjoy to-good-to-be-true-why-don't-you-pinch-me kind of relationship buddings without disclaimers, walls and guards. To be momentous, to be as present as possible, to roll with it, to savor it with a big open heart channel takes courage, bravery and balls - because you know the risk of having an open heart on the line.
The matters of the heart are delicate and tender in that space more so than ever, but not everyone is ready to receive that most beautiful gift of the open heart - and therein lies the (potentially galling) rub.
Namely, if an indecisive aspect of a recent pairing is uncertain over the aforementioned pairing with an other more-certain-about-things aspect, then the relationship is bound by uncertainty as the limiting reactant that holds the space between them with question. Until both move ahead together onto certain grounds, they will be at 2 different places in reference to that notion of togetherness.
(Likewise, if the exuberance about an other that is expressed isn't authentic joy, it's simply an attachment to those amazing feelings of in-loved-ness and fear that those emotions might fly away as fast as they landed. It's worth being honest about that in the chemical haze of lovely beginnings.)
On the other hand, to be met with an open heart in its fullness of expression and to be seen for all that you are by another open heart of the same magnitude is clearly where its at. Anything less might not feel quite right - and being able to articulate that vibe (at any point along the way) is a monumental clarion call. Those intuitions are key signals asking for a voice.
Being OK with unknowns is a good practice. Fears, baggage and insecurities fly up in the space of no details or plans, or lots of 'ifs' with no definites in sight. And, sorting through all of that is a worthwhile exercise so that one can learn the beauty of the momentous present unattached to any illustrious future outcome. (Remember: Life is not about answers, but rather uncertainty and handling that with grace.)
And, somewhere in the enmeshment and boundaries, is the lesson of letting go fully. Because enveloped in love's meaning is a clause about freedom from attachments and restrictions - and that kind of love includes being able to let go fully of the being we love with that very same open heart that embraced their wholeness at the start. (Love is a verb. It moves.)