Speaking to Soaplife, the actor disclosed that co-star Jo Joyner had suggested the Albert Square pair's current sex issues.
"This storyline was something that Jo felt was important," he said. "One of the things that came out in the research she did was the effects that cancer treatment has on your sex life.
"Given that Max and Tanya's relationship was quite physical, then it would have profound effects."
The EastEnders icon remained coy about Max's mysterious trip to Manchester, but insisted the "incredibly exciting" resolution will soon "emerge".
The 39-year-old has previously maintained his stance that Max will stand by Tanya throughout her illness, despite having a fling with Roxy Mitchell (Rita Simons).
Of Max and Roxy's chemistry, Wood added: "He's not having sex at home and Roxy is more or less willing to put it on a plate, and for Max - that's always going to be a struggle.
"There's an element of game-playing and I think there comes a point where neither of them know if they are playing a game, or if they are actually interested in one another."