<human>: I met him on tinder back in July and we sort of clicked right away. We started talking every day and on the 5 date he asked me to be his girlfriend, which caught me off guard because initially he said he's not sure that he wants a relationship with anybody and that he prefers casual things. 
I myself have just gotten out of a 4 year relationship and was pretty depressed and reluctant about jumping into another relationship. So I told him from the beginning that I'm also not sure about what I want regarding the two of us but I would prefer if we could take it slow and get to know each other, to see if there is a connection. We hadn't slept together yet when he asked me to be his girlfriend.
Since then, things have been going great from my point of view and I feel that I've fallen in love with him and I find myself always thinking about him and getting butterflies in my stomach every time he send me a text or calls me. He introduced me to all his friends and his brother and sister in law and a month ago he changed his relationship status on facebook. 
Last night we were at his place and he said 'I think I will be falling in love with you' and although he said it in a sweet kind of way, it kind of left me feeling sad because I already know that I'm in love with him and was hoping that he will say that he loves me. I didn't let it show that it made made a bit sad and I gave him a smile and a kiss. 
I really want to tell him that I love him but I don't want to jump the gun and mess everything up and I would prefer it if he said it first. Since we've already been together for 4 months now, I don't know for how long should I wait for him to fall in love with me. 
After how long have you told your significant other the 3 magical words?

Summarize the given text in a few sentences.
<bot>: Been together for 4 months, I'm already in love with him, he told me he thinks he will fall in love with me