Sorry, but that sounds like a terrible plan to me!
First of all, I've been going through all your threads and agree with others who have suggested that you seek a therapist concerning your feelings of guilt connected to your sexuality. You should not feel guilty for your sexual or romantic feelings. If that is not possible, I suggest you find an out homosexual friend that you can talk to in real life. There are People who can and will help you.
The thing with this guy has been going on for a long time now. I still am not chrystal clear on some of the details (how do you end up showering together at exactly the same time every day?) but from your description I would say that probably, you are more into the guy than he is into you (sexually or romantically). However, I would definitely say that he does have some kind of interest in you (it might just be mind-/powergames or a mild homosexual curiosity on his part, hard to say).
Now, last time you have masturbated in front of him and he didn't immediately leave when he noticed that ( and from a european perspective, there is no reason to feel guilt about this either!). So this has defenitely changed your relationship. I would definitely wait and see, if he adjusts his behaviour the next time in any way. If I wanted to take it a step further, I would play back the steamroom comment (you said yourself, that you kind of froze and fucked up when he made that comment). Next time you see him, tell him that you're going to the steamroom. If you want to be more adventurous, use the exactly same phrase that he used back then. Then see what happens.
I would not say 'I like you', as it is a bit too strong. It exposes you directly. And I wouldn't do that in your situation. Especially, if the guy is just playing with you, for whatever reasons. So, whatever behaviour you interpret as an interest in you from his side, just kind of play it back at him.
Also, you could quite innocently tell him that you're going to change the gym and see how he reacts to that. If he is interested in you, the least thing he will do is express regret about that.
And not showing up for three weeks is not a good idea either, that sends mixed feeling an would totally confuse him if he is interested. It also wouldn't get you any further.
Also, I'd say you have to wrap this up somehow soon. A few more attempts in this direction should be enough. If that doesn't get you anywhere, move on. Forget about him. And start dealing with your own problems with your sexuality first.
I hope that helps a bit and let us know how it goes (in this thread, please).