Now I'll give you some statistics from England&Wales.
Here are the percentages of South-Asian British men intermarried with white women (from the 2001 UK Census):
Indian: 4.86
Pakistani: 3.65
Bangladeshi: 2.16
Here are the percentages of 1.5/2nd generation South-Asian British men intermarried with women of a different ethnicity (from the 2001 UK Census). These are statistics for British-raised South Asian men:
Indian: 19.46
Pakistani: 10.46
Bangladeshi: 19.23
The above figures include intra-South Asian marries (ie Indian marries a Pakistani) and also interethnic marriages with other non-white groups. If we want to get the percentage of 1.5/2nd generation South Asian British men who intermarry with white women, here are the rough estimates I calculate from the Census data (figures are approximate):
Indian: 11.2
Pakistani: 4.2
Bangladeshi: 7.6
I was curious about figures for interracial cohabitation, as cohabitation is a better proxy for "dating" and sexual behavior. Some have suggested that there's a tendency for South Asian men to date other races, but marry their own. So here are some interethnic cohabitation rates for British South Asian men and women. These figures are based on calculations from the UK Census. Methodology can be provided if requested. These figures are estimated
lifetime probabilities of cohabitation for South Asian youth in the UK. These youth can be of any generation, but primarily 1.5 and 2nd generation.
Probability of UK South Asian youth male cohabiting: 17%
Probability of UK South Asian youth female cohabiting: 15.5%
Probability of UK South Asian youth male cohabiting outside of race (ie with a non-South Asian): 8.3%
Probability of UK South Asian youth female cohabiting outside of race (ie with a non-South Asian): 6.8%
Interestingly, the probability of interethnic cohabitation for UK Chinese males was somewhat higher than for UK South Asian males. UK Chinese females cohabiting far more than UK South Asian females also.
Lastly, here are the probabilities of having contracted chlamydia, by ethnicity. These probabilities are based on a large-scale national chlamydia screening programme in England. These screenings only look at those in the 15-24 age range, so they apply to UK South Asian youth. Also, these screenings are based on those who submit to chlamydia testing, so if a more culturally conservative group opts not to test, that wouldn't distort these results.
These chlamydia positive rates by ethnicity are a good indicator of sexual promiscuity, as chlamydia can only be contracted through sexual activity.
As you can see, females and especially males from the Asian subcontinent (ie India, Pakistan, Bangladesh, Nepal, Sri Lanka) have much lower rates of chlamydia than other ethnic groups. Even lower than Chinese men and women. As a group, there seems to be particularly low rates of sexual activity among UK South Asian youth males.
The US govt keeps it's own statistics for chlamydia. Based on my analysis, it seems that even in America, there seems a pattern of chlamydia rates for men being in this order: Black, Hispanic, white, East Asian, South Asian. For women, the pattern is similar, except some studies indicate East Asian women might be equal or slightly higher than white women. Interestingly, it seems lifetime probability of chlamydia infection is equal for UK whites and American whites.
I explored that possibility that variations in chlamydia rates, by ethnicity, could reflect different rates of "safe sex" practices. However, this seems unlikely, as British South Asians and British whites have equal abortion rates. If British South Asians observed safer sex practices more frequently, we wouldn't see equal abortion rates. (By the way, the overwhelming majority of British abortions occur to young unmarried young women. This is also true of South Asian women, among whom the overwhelming majority of abortion seekers are young women.) It seems that low chlamydia positivity among UK South Asian males and females is more a product of relatively non-promiscuous sexual behavior, rather than any differences in safe sex practices.
TLDR: As we can see, intermarriage rates (with white women) for British-Indian men are about the same as those of Indian-American men. Other South Asian groups (Pakistani, Bangladeshi) intermarry less.
Cohabitation rates are comparatively low for South Asian youth males and youth females in the UK, but the men are slightly more likely to cohabit before marriage. Both groups have low rates of interethnic cohabitation.