To me it seemed pretty straight-forward that future Trunks would prefer the company of his own version of Bulma. Arguably she’s the most experienced, but also he just has the closest relationship with her, I think. That being said, he has definitely shown signs of attraction with her younger counterpart in the main timeline of the show, and I think I could see him hooking up with any version of her he might travel to see. How many he actually has visited is probably up for debate (in the source material time travel is presented as a costly and difficult thing), but you’re welcome to use your imagination. It’s fun to imagine Trunks traveling to the younger Bulma of Dragon Ball or the alternative older version from GT or something.
Also, I decided to use the blue-haired version of future Trunks because I like how it serves to separate him from the main version. Obviously it doesn’t make a whole lot of sense why his hair is blue now, but there you go.