Of course, in our culture, it is common for men to be uncommunicative, except for the bare necessities, and to dismiss or tamp down emotions.
This works great on the battlefield or during the hunt, but it's not so good in romantic relationships.
The first word in practicing polyamory is "communicate, communicate, communicate." Do it often and do it well, clearly, respectfully. Talk, AND listen. Delve deeply into your desires, needs, emotions, plans for the future.
Obviously, your guy is not on the communication train. He is not likely to change... or if he does, it will be slowly, and probably frustrating.
This is why I love being partnered with another woman (well, one of the reasons). We talk everything into the ground, including our feelings and doings with other partners. My male partner is also not a traditional male. He IDs as genderqueer and loves to discuss multiple angles of any situation.
If your out of town bf insists to you that the woman he sees every night, and loves, is peripheral to his life (!), what does that tell you about how he must see YOU, who lives further away?
He wants to keep things casual. Fine! If he's fun when you're together and doesn't do anymore douche moves like seeing his other gf on the first night of your visit (wtf?), enjoy what he can give you, limited as it is. Plan to focus more on building relationships locally so this guy and his other gf can be less on your mind.
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
Mags (poly, F, 61) loving miss pixi (poly, F, 39) since January 2009, living together since 2013
"Master," (mono, 34), miss pixi's Dom for 2 years