Husband timid with sex

My husband is a fantastic man. He's kind and thoughtful and respectful and honorable. We differ in the sex department though and I'm not sure what to do to bridge the gap. No matter how many times we discuss it, he doesn't seem to understand that I need more than just a kiss moments before he wants to have sex (that's how he makes his move). I want foreplay and flirting leading up to the deed. I've tried to flirt with him to lead by example. I've sent him naughty photos and texts and left little notes. I've made naughty games and bought countless pieces of lingerie and set up whole seduction scenes but he never returns the favor. I think he's uncomfortable with anything overtly sexual. I've suggested sexting but it makes him feel ridiculous, like whatever he says is stupid. I found 19 questions from a podcast to open communication about sex but we only made it through the first 3 questions. I go down on him frequently but he has only returned the favor twice in 2.5 years. I don't know how to ask for it as he would never ask me to go down on him. He can't even tell me what turns him on or any fantasies he has. He says he doesn't know. I just want to see my husband lose control. I want to feel wanted and not just respectfully cherished. Especially now that we are trying to conceive. Sex so frequently becomes about schedules and tests... Also, he did get tested about 8 months ago and has low testosterone which was making him tired and killing his sex drive but he's on medication and at normal levels now.