You should say I love you first. And no, you should not be making excuses in your head. Sure, the situation could become awkward if he does not reciprocate your feelings. But those three simple words hold so much weight and meaning to him, and therefore, it is highly unlikely that he will walk away from you without at least giving an explanation.
I know you are scared. Many “I love you’s” turned into goodbyes in the past, and you are traumatized by love because it reminds you of being abandoned. I know you are scared of love and affection due to being left.
But even if it ends up being unrequited love, or even if he is conflicted about his feelings towards you, say it anyway. In love and life, we do not get many second chances, so take these opportunities that come and live without regrets. Be brave enough to make the first step sometimes, and be vulnerable and bold enough to say to the person, “I love you, even if you do not love me back.” Because in a society where we are all taught to be emotionless and dispassionate, loving someone and telling them you love them is quite a heroic feat.