Some thoughts:
The “rite of passage” thing: OK, maybe strip clubs don’t tickle your fancy, but from what I gather from DDG, in this young man’s family it really is a tradition to take the young man to a stip club on his 18th birthday. Whether you approve or not is, in many ways, irrelevant unless you are part of his family. Other families have traditions like the First Hunting Trip, Drinking Until You Puke When 21, and so forth. Presumably, once he is past his own “rite of passage” he may be expected to participate in other instances of this family tradition. So the question is likely to come up again.
Facing questions like this is part of early adulthood. The young man is being put in a spot to either keep his girlfriend or keep his family traditions. He needs to figure out his position on this, preferably before he gets married to anyone.
The lying issue: Lying in a relationship is not cool. Period. However, I’m not surprised that someone of his age would be tempted and not surprised he would do it. Understandable, but not to be condoned. Girlfried has every right to be upset about being lied to. Girlfriend and boyfriend need to sit down, exercise a little honesty, and work out this lying issue in particular.
The Power Play: As has been pointed out, this is girlfriend and boyfriend, not man and wife, or even a pair of fiancees. Either party enjoys a great deal of freedom outside that relationship. There are some limits - dating other people, for instance, if there is an understanding of a “steady” relationship - but neither controls the other. Girlfriend can certainly state her feelings and opinions, but she has no authority to limit boyfriend from going to a strip club with his family (and just how far is this young man going to go with his family looking on?), particularly if it is a family tradition. She may decide she wants nothing to do with a man from such a family – this is called a “life lesson”. She will encounter many more in years to come. The strip club/porn picture/male lust practices are items she needs to think about, her feelings about them, what she will and will not tolerate, and consider those feelings when making long-term relationship decisions.
Boy Lust and Girl Lust: Men like to look. This is not news. Actually, men often like to do more than just look, but they will often settle for just looking. Even men who don’t look still feel the urge to look This is part of being a male human being. Now, some men look whether their women approve or not, other men will not risk the wrath of their women, and some men feel it is wrong to look when you’re committed to someone else. Note the wide range of actual male behavior that comes from this basic urge. Women need to consider the behavior of a man when considering long-term relationships, and it does help if the man and woman discuss some of these hot topics early on. Maybe not the first date, but some exploratory questions along the lines of “how do you feel about strip clubs and porn?” about the same time you’re determining stands on “sex - before or after wedding vows?” is a very good idea. If a man has a habit of hitting the clubs on a regular basis she should not expect much change after marriage (it’s possible - but could also become covert, leading to much erosion of trust and other ugliness)
Now, we should consider women and THEIR urges - women’s urges and feelings in the past have not always been taken into account. Just as there is an urge for men to sow their wild oats (whether they actually do so or not, the urge is there), women have an impulse to Deep and Meaningful Relationships, sometimes called “romance”, but really (I think) connected to getting a loyal mate who won’t desert when she gets down to makin’ babies. (Note: This does not mean I feel that’s what a 19 year old young woman should do, or that that is the only function of women, just that it is one of many impulses that affect behavior). Thus, young women are frequently insecure about their relationships, even if they don’t conciously know why. They’re afraid - nay, terrified - of dersertion which, in the bad old paleolithic days, could mean disaster for her and death for her offspring. It’s biological baggage. Heck, nowadays male desertion is still a bad thing for mother and her babies. A result of this insecurity is that young women ask their young men to do things to “prove” their love, committment and loyalty. Such as “don’t look at other women” and “choose me over your family”. If you think about it, on a certain level, that’s exactly what girlfriend did - ask boyfriend not to look and to choose her over family. Now, a wife can ask her man to choose her over mama - a girlfriend can’t. She may want to, but they aren’t at that level of commitment (yet). Young women can become very possessive and jealous, and quite a bit of it comes from this desire to achieve a permanent pair-bond. Just as we expect young men to control their lust and not attack every human female they encounter, young women need to control their urge to control young men. She may want to be the sole focus of his life, but most likely she isn’t. If she is, that could be a very unhealthy situation, to be honest.
So… young men need to learn that it is not acceptable to lie to young women, and that many young women do not approve of certain activities that young men are strongly attracted to. They will also learn that many women demand tests of loyalty and love, and young men need to decide how far they will go with such requests.
Young women, whether they approve or not, need to understand that certain activities are strongly attractive to young men. They need to decide how they feel about said activities, and consider their tolerances when choosing to date young men. Young women also need to understand that young men are not playthings but also human beings (even if they don’t always seem to act like it, from a young women’s perspective) and there are sharp limits to what a girlfriend can ask/demand of a boyfriend. There are limits to what a wife can demand of a husband.
Both parties must understand that lying is extremely uncool. They need to discuss even the bits that are uncomfortable to discuss. In fact, it’s the uncomfortable bits that most need to be discussed. A longterm relationship might require compromise - for instance, if we were talking husband and wife, might be that wife allows the strip club adventures ONLY in the family tradition context, but husband agrees to stay away otherwise. But that would only apply to husband/wife or extremely long-term relationships (I have a cousin who’s lived with the same man for 50 years - they’re not married, but obviously many of the issues of marriage apply).
DDG - I applaud your approach to the daughter’s plight. You seem like a reasonable parent, and goodness knows, we need more of these.