Now DH wants to wait

My husband's dad is a bit unwell and basically has stopped taking care of himself. Not the first time this has happened since we've been married but now my husband wants to postpone TTC and suggested I go back on birth control. I'm coming towards the end of my TWW (AF due on the 24th). His decision to want to wait again is quite a shock because we really thought long and hard about it and discussed it before deciding to try. And it concerns me because he decided he wanted to have another baby before he's 40, which is only 2 and a half years away. I thought we were both ready for this. I feel kind of heartbroken by this change.