I have been married for almost 18 years and have recieved many text messages from women and I take the number and call them and say you have the wrong number or just don't respond so if you believe his excuse then let it go if not or you feel mistrust then get it out in the open right away be honest as this is the only way you can either clear this up or flush him out of his cheating hole. He doesn't sound like he is a cheater but have you ever heard about him before you met him like friends teasing him about former flames or is he protective about his past ?? TALK FIRST then get down to brass tactics. I am Male so hopefully this will work GL
You need to just let this go. Unless he has a history of causing you distrust in him among other women, this text thing sounds completely harmless.
First of all, couples in committed relationships are still allowed to think another person is attractive, and even compliment the attractiveness. It doesn't mean they're going to cheat on their significant other or even have any intention of cheating. I doubt he finds this young woman more attractive than you. And if he does, it's no big deal because that doesn't mean he's going to act on his feelings and cheat on you. I know plenty of men who are extremely attractive and I talk to them all the time, but that doesn't mean I'm going to two-time my boyfriend--I'd never dream of doing that and the thought wouldn't even cross my mind.
Secondly, the girl he texted clearly felt he was overstepping his bounds and notified you immediately instead of leading him on in secret. So she respects you and your marriage, which is a noble characteristic that seems to be a hard thing to find in people these days who seem to think they can take what they can get when they want it, married or not.
Thirdly, he apologized to you and has vowed to never let it happen again, and has claimed he never had any intention of cheating. Is there some reason you have to not trust him?
Be careful not to let your jealousy get the better of you, forgive your husband for causing you this jealousy and insecurity, and move forward.