Ann, I am sorry to say but this is a sad story of betrayal but not love.
Mature human (especially with an infant in arms) should give an account himself and control own emotions. Intelligence along with the ethics and wisdom it something that distinguishes human from animal. People who put their emotions and instincts in front of mind and ethics usually are left near broken launder eventually. No regrets about your girlfriend (or whoever it is). Merely about her innocent child who was left without bio-father and is doomed to drag out a miserable existence.