It would be nice if your bf would send you little text messages throughout the day. A good morning, a good night message at least. If you'd like that, tell him, and make sure he lets his OSO know that he will be doing that so she makes space for him to do so. Just tell him you'll be struggling a bit with jealousy/envy. A partner going abroad for a month, to an interesting location, could make any partner, mono or poly, envious! It would be lovely if he could share daily something about what he saw and did that day.
My gf has done this when she's traveled without me. Telling me about her adventures, how much she loves and misses me, how she tells other people about me and how much I mean to her, etc. It's very sweet and keeps us feeling connected despite the distance.
Love withers under constraint; its very essence is liberty. It is compatible neither with envy, jealousy or fear. It is there most pure, perfect and unlimited when its votaries live in confidence, equality and unreserve. -- Shelley
me: Mags, 59, living with:
miss pixi, 37