About to come out to my wife. Need some pep talks.

I'm a 31 year old man with a wife and 3 year old son. Due to a whole bunch of internal and external issues throughout my life I've spent most of it denying the fact that I am gay.I've been working with a therapist on this and on Friday I came out to my brother and his girlfriend. They were both super supportive and definitely helped me feel like I am ready to have that talk with my wife.I've written a letter that I want to read out loud to her but I keep chickening out. The past two days I've spent telling myself "tonight is the night" but once our son is in bed we're both exhausted and I just can't bring myself to do it.I'm really thankful for all of you guys sharing your stories on here. Lurking on this sub has really been helpful to me. Any words of wisdom would be so appreciated. I know I just need to pull the trigger but in the moment I get scared and freeze up.Tl/dr: I need help telling my wife that I'm gay.