He said WHAT?

So I've had this FWB on & off for 6 years now. We dated 9 months ago for about 4 months & got pregnant. We ended up having a miscarriage & then broke up over a misunderstanding. We've just started fucking again at the beginning of June, and out of nowhere he just texts me saying "I love you". I'm at a loss of what to say lol. I mean, don't get me wrong.. I do have love & feelings for him, but I thought we were just fucking? So I've been keeping my feelings out of it. This is the only time he's ever told me he loves me.

How should I take this? What would you all do?