The purpose of the mind is to protect the heart.
I believe you have to use your head to make decisions with "awareness". Ignoring red flags when selecting a mate leads to problems. One has to knowingly make a calculated decision when choosing to make an "emotional investment" in someone.I talk a lot about this in my book, "My Cat Won't Bark! (A Relationship Epiphany).
Each of us (chooses) our own friends, lovers, and spouse. Love doesn't "just happen" a lot of saying "yes" has to happen prior to someone becoming an "item". Yes to an exchange of contact information, yes to a date, yes to a kiss, yes to spending more time with one another, yes to sex, yes to becoming "exclusive" yes! yes! yes!. Any "no" would have stopped things!
Hopefully with age comes experience and maturity which leads us to (think) before we say "yes". (One has to truly know themself, what they want and need from a mate before they (decide) if someone has those traits). You are responsible for your own happiness! If you go to the store to purchase an apple but buy an onion instead whose fault is that? It's a waste of time and energy to curse the red onion for not being an apple. Ideally we learn to become better (shoppers) in the store of love. :-)