just use a multisig

both sides send a public address to each other
use those addresses as a 2 of 2 multisig

fund the multisig and then when its funded you both have to decide on the destination of the fund(s) which you then both sign for

no middle man needed. just each other being co-signers to make sure it only leaves the multisig when both sides are happy with destination and amount and time to let it be spent

in short you both become your own escrow