Oh dear.
I feel bad for you that you had such a dysfunctional start into romance with F. That was unfair for him to do that to you.
But I feel worse for M. You're looking for something that does not exist in a long-term relationship. You're looking for those sparks that only happen at the very beginning. The poor guy could work his whole life to make you happy this way and never succeed. You need to find a way to be happy with the every day "comfortable" parts of a long-term, committed relationship. If you can't, then you need to be fair to him and end it. Then go find your fireworks with multiple new people until you get bored of it and realize you finally long for a committed relationship.