In Kuntresei Shiurim Bava Basra Kuntres 9 Shiur 1 § 4 by Rav Gustman, he brings a couple of sources related to your question.
First, he brings the Yad Ramah Bava Basra 26a § 107 by Rav Meir HaLevi Abulafia, who writes:
דאסור למיגרם מידי דאתי מיניה היזקא לאינשי אי משום לפני עור לא תתן מכשול ואי משום ואהבת לרעך כמוך
It is forbidden to do anything which will cause damage to another. Either because of the prohibition of lifnei iver, or because You shall love your neighbor as yourself.
Rav Gustman is bothered that what relevance is there here to lifnei iver? He understands it to mean that one is causing themself to stumble, in the prohibition of damaging others. Rav Gustman says we see from here that just like it is prohibited to cause others to stumble in prohibitions because of lifnei iver, so too it is forbidden to cause oneself to stumble.
He brings another source for this idea from Teshuvos Beis Ephraim Yoreh Deah § 54 by Rav Ephraim Zalman Margaliyos:
ופשיטא דאסור מדאורייתא לעשות דבר המביאו בהכרח לידי עבירה שהרי אפילו לגרום לחבירו לעשות איסור אסרה התורה וכו' שאסור משום לפני עור וכו' ואף שאפשר שזה לא יעשה האיסור וק"ו בן בנו של ק"ו שאסור ליתן לפני עצמו מכשול ודאי שיבא בהכרח לידי עבירה דאורייתא או דרבנן
It's obvious that it's biblically forbidden to do anything that leads one to definitely transgress a prohibition. For behold, the Torah prohibited even to cause another person to transgress a prohibition...it's forbidden due to lifnei iver...even if it's possible the person won't transgress! All the more so it's forbidden to place a definite stumbling block before oneself, such that they'll definitely transgress a biblical or rabbinic prohibition.
I just want to point out that both of these sources are either dealing with or explicitly mention cases where there will definitely be a transgression caused. In your specific question of buying forbidden meat, I don't know if that would be called a definite. Maybe it depends on how much of an addict this person is for forbidden meats. But at the very least, we see this concept exists, at least in some form. It requires further study to see exactly how equivalent lifnei iver to others is to lifnei iver to oneself.
For what it's worth, I also found on Otzar HaChochmah that the editor of Reshimos Shiurim, the teachings of Rav Yoshe Ber Soloveitchik, on Yevamos 5b fn. 194 has a relevant point. The Brisker Rav brings that according to the Ba'al HaMeor, it is biblically forbidden to cause oneself to have to enter a situation of pikuach nefesh (saving a life) on Shabbos where they'll have to transgress biblical prohibitions (albeit permissibly, as is the case with pikuach nefesh). The editor suggests the source for the prohibition could be lifnei iver. Again, I'm not sure if this is referring to a definite cause of pikuach nefesh, but it sounds like even where it is only a likely possibility. This could be more relevant for your meat purchase question.