According to the psychiatrist I pay most attention to, James F. Masterson, children who grow up under mothers who require their children to meet their own unmet needs for attention have a very difficult time nurturing what he calls their "real self." What happens is that the mother's strongly averse reaction to the child's first sign of autonomy, which occurs when as an infant s/he first started walking, and which kicks in hard once again at adolescence, scares the child away from full (or even partial) self-realization. In the way of the path ahead to ever becoming his or her real self are fears and pains arising owing to feeling abandoned, which are so paralyzing they're akin to what reliably blocked Truman from just driving across the bridge and leaving Seahaven in The Truman Show. He calls them the Six Horsemen of the Psychic Apocalypse: Depression, Panic, Rage, Guilt, Helplessness, and Emptiness. What happens to such children? They never really grow up, never really individuate. Ryan Reynold's Wade shows signs of being exactly this sort of person. At first, he's the kind of guy who seems mostly motivated to deny parts of himself he is concerned actually best represent him by bullying those in overt possession of these traits—geeky guys who wear their vulnerability on their faces and who rage powerfully at women. So it's not him, it's the guys he bullies. He becomes someone however who actually enters a real relationship with a woman, one with promise. But as soon as he gets past the period of mutual-gaze infatuation and enters that period where his relationship might challenge and mature him, take him adrift from his past life of being just another member of a homosocial gang, a calamity happens (here his developing cancer) which leaves him essentially living with his mother, fretful of women rejecting him (my god! my acne!), wantonly acting out his aggressions, and associating with those without the sophistication to see through him (here the simple-minded proletarian X-Men, Colossus, as well as the petulant sorta one, Negasonic Teenage Warhead).
This is the first R-rated comic book film, but in truth what's on display in terms of characters relating to one another is mightily regressed from the adult relationship we saw on display between Tony Stark and Pepper Potts in Josh Whedon's the Avengers. It's too bad it's doing such good business, because it puts the pressure on recognizable adult characters in other superhero films (like McAvoy's Charles Xavier) not to make him wilt—and not making him wilt, is the other reason why the X-men's mansion is always empty when Deadpool visits it, one he wasn't actually going to admit to (or indeed even allow himself to remain for long cognizant of) when he breached the fourth wall, wink, wink: Storm, Cyclops, Wolverine, as they've been depicted thus far, would have no truck with him. May they never be forced to pretend to be willing partners in his sort of retrograde.