How do you get him to be your lover & friend?

YES!!!!
That's exactly the invisible wall I want this romantic-friendship to take on. That of being THE OTHER WOMAN/MAN. Hammer on the nail. smile
I will not do that though, I want someone who can take photos with me, be out in public with me and won't be depressed about his unhappy situation. I want things to remain as light as possible. But like any other friend of mine, I will be there in hard times, just don't want to walk into certain kinds of hard times expecting to have fun.
I like the idea of the 4mos rule. The plan is basically between May 1st and Oct 1 (at most). I am aware that I may go through 2-3 friends during these warm months. That's fine. I am going to try hard to prevent that though. Yes, people get bored with routine, and yes people grow feelings. Nothing is completely controllable. But, I guess at that point we have to call a time-out and discuss things. That would put a huge damper on the fun and security the plan will bring, things might turn awkward too. If possible I'd rather we hide the feelings til after the summer.