Haley Kalil Could Have Figured Out Sex With Huge NFL Ex, Sex Therapist Explains

Haley Kalil says sex with her NFL ex-husband Matt Kalil was damn near impossible because of his oversized manhood ... but a renowned sex and relationship therapist is explaining how they could have made things work in the bedroom, and she's got pointers for other couples going through the same issue.

Here's the deal ... Haley went on a podcast recently and revealed the biggest reason for her divorce from the former NFL offensive lineman was the fact that sex was difficult because his penis was the size of two Coke cans.

Dr. Laura Berman listened to Haley's complaints and tells TMZ ... the SI Swimsuit model is far from alone in finding it difficult to bang a partner who is oversized.

While the good doc stresses bigger is not always better, she says there are plenty of ways for women to fit a big penis in their vagina ... telling us communication, lubrication, foreplay, planning, and slow playing are key.

Haley said she would be in pain when she tried to fit Matt inside, but Dr. Berman says the best thing a guy can do in such a scenario is to communicate with the woman and not rush her ... she says vaginas can expand -- babies come out of them after all -- but if the woman is worried about pain, they can tense up.

The Kalils aren't the first couple to separate because of a big penis, the 'Sex Magic' author tells us ... and she says it's a good idea for couples to try and plan sex so they can prepare mentally and physically to get the deed done.

Haley said Matt's bigger than most guys, but fellas and ladies out there dealing with this sort of thing will want to take notes ... Dr. Berman is taking us all to school.