Regina Santos-Aviles' Husband 'Surprised' Rep. Gonzales Fessed Up, Bowing Out

GOP Texas Rep. Tony Gonzales ended his reelection bid this week after admitting to an affair with a former staffer who later died by suicide ... and that staffer's husband is stunned by the developments.

Here's the deal ... Gonzales terminated his campaign Thursday, the day after he admitted to an affair with Regina Santos-Aviles -- a woman who worked for him while he was in Congress. Initially, he said he would not end his reelection bid.

Adrian Aviles tells TMZ … he's surprised Gonzales finally "took some accountability" and told the truth about the affair … and he's "satisfied" that it appears Gonzales' political career is over.

Adrian tells us he exposed his late wife's affair to "show people who Gonzales really is" ... and he assumed the politician would keep lying to save his career.

While Adrian calls Rep. Gonzales admitting the affair and dropping out of the race positive developments, he worries about his own 8-year-old son he's now raising alone ... because the child may never truly get closure after losing his mother. She died in September last year after setting herself on fire, Texas Public Radio reports.

Right now, father and son are on vacation and mostly unplugged ... but Adrian was aware of the major developments.