H-bridge Current Regulation?

hi,

so i've been trying figure out way regulate current of h-bridge , can't seem wrap head around it. basically, need current across load @ current (say, 5ma), given changing load resistance. achieved using , h-bridge built using spdt relays (or dpdt) switch polarity @ set time intervals , digital pot regulate voltage... ideally circuit not using relays due noise.

am right in saying unachievable using digital pot , h-bridge ic since voltage has taken wiper - provides positive voltage? or controlling voltage source of h-bridge work? (sorry, i've never used them before!)

i've thought of using current regulator lm334z won't work in series load either since can't handle reversing polarity......

any mucho appreciated . there's simple solution i'm missing.

normally h-bridge either full on 1 direction or other, or off altogether. lower drive capability, h-bridge pulsed on/off different durations, pwm signal example controlling width of on-pulse.  pot can used analog level, read , change pwm value accordingly.
the supply voltage not changed; nor transistors make bridge turned partially on, makes them operate in linear region on-resistance higher, vs saturation region on-resistance lower , can run cooler.

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