To my knowledge, the cause and effect link has not been well established, as is the case for other types of difficulties. I certainly do not want to minimize the effects of sexual assaults, that are horrific both for women and for men, but we can make someone fragile who is not, and make someone who is in distress even more fragile.
Suicide is complex. The factors that make people vulnerable to suicide are also complex. There is no single cause for suicide. I don't know if there are specific data showing a link between sexual assault and the suicide of military people.