How do I twll my fwb that I've caught feelings for him

How do I twll my fwb that I've caught feelings for him
We have been chatting for a few months and have slept together four times. We text almost every day and get along really well. When we do 'hook up' we make a night of it and go and have a few drinks and spend the whole night together. We kiss in public and a few weeks ago he held my hand when we were out. He's said things to me before like how he's not liked anyone for a long time and he is really caring and treats me with respect. When we leave each other after spending the night together, I can't stop thinking about him and it makes me feel sad and lonely and often quite depressed. I have no idea how he feels afterwards. I caught feelings for him a couple of months ago but have never mentioned anything to him for fear of making things awkward and putting him on the spot but it is quite torturous and I feel like I need to say something. Now, the problem is I'm quite shy and seldom talk about my feelings. I also don't want to make him feel super uncomfortable and awkward so I would rather do it over text so that he has time to think of a reply. So how would I begin that conversation? I am scared about doing it because I don't want to lose our friendship and it will definitely be awkward if he rejects me but I'm desperate to get this off my chest?????