Lanet,
The fact that your DH had white blood cells in his semen is a GOOD thing. The antibiotics are used to treat a presumptive case of prostatitis. I have a couple friends who've come back with WBC in their semen, did their course of doxycyline, then 2 months later, their semen test was dramatically better. Also the percent motile sperm is relevant to the total concentration of sperm. If you has a really high count, but only 15% are motile, thats still ok compared to having a very low count with 25% motile. In any case, his semen parameters will get better after the antibiotics course. Hoping your BFP is right around the corner.