i can see this is more about you than him. you are worried he will think you dont miss him or have forgotten him - trust me he wont - you are his one and only mummy and you have that honour for the rest of your life. if you call at night before bed he will be very unsettled and will prob pick up the emotion in your voice. what he needs is time with dad and when he comes home he will be so excited to see you. he will have missed you and he will give you a lovely cuddle. im sure dad will send messages of how he is and if you have a good relationship im sure he will send some videos too of his adventures.
When my husband and i went away on honeymoon we left our kids with my parents for 4 days. we did a little hand made book just using paper and string. each day we wrote a message to the kids which they could read over breakfast with grandparents. it was something like this (below). very upbeat, a bit interactive and it went down a treat because it showed we loved them, we thought of them, but we had to be mummy and daddy for a few days while they had grandparent adventures. not too sentimental or emotional as we didnt want to evoke any upset. just something fun they could incorporate early in the day and have fun with.
Day 1 - well i hope you had a lovely sleep at (insert place). is your room nice? was your pillow comfy? which teddy did you bring with you? daddy and i are planning to do XXX today, i wonder what you are doing? why dont you drawa picture below of all the things you have done today using some crayons.
Day 2 - today daddy and i are going to climb a mountain - its very high and i hope i can touch the clouds with my hands, i have a mission for you today - i want you to collect something special from your day and keep it safe for me. i want to hear all about it when i get back. a shell .. a leaf.. oh i do wonder what it might be...
Day 3 - today daddy and i are going swimming in the sea, i hope we see lots of colourful fishes. whats your favourite type of sea creature? why dont you draw it below and when we get back i will tell you if we saw one.
Day 4 - only one more sleep until we come home on the big aeroplane. when you are bigger we can take you on an aeroplane too - where do you think you would like to go? Africa to see giraffes and lions, new york city to see the big sky scrapers or maybe australia to see the kangaroos!?! have a think and tell me tomorrow. more excited to see you than christmas.