For a semi-civvie fuck buddy there are so many ways to provide an “allowance” without making it seem transactional.
Many of the DH want a “bf” style friendship and crave meeting someone regularly who isn’t a flake or an idiot and treats them with respect.
Just set the ground rules early on ie “this is not a serious relationship but I like meeting you and fucking you”. Obviously not in so many words but you get my drift.
From the infamous “taxi allowance”, or just topping up their Octopus card, offering to buy them a nice piece of clothing/jewelry or even groceries. The options are endless. Of course just agreeing to a straight up cash allowance per meet works too.
Tip: if you decide on a straight cash deal, put the cash in a colorful envelope with a card …makes it feel less like a “wham bam thank you ma’am” type of deal. And the girls love it!