Dear Carolyn:

I have been in two long-term relationships, but now I'm in the first one where I really care about the guy. "In love" kind of stuff. I have never been the jealous type (thought I wasn't at all) but I have found that's not the case anymore.

The problem is, his ex-girlfriend of four years is returning to town after being gone for about the time we've been together, and they are best friends. I've never met her. I don't think he's going to sleep with her, or want to get back together, but I'm afraid he'll talk to her all the time and want to hang out with her all the time, without me. I know jealousy is centered in insecurity and lack of trust, and I know it's illogical. I just don't know what to do about it.

I've tried talking to him about it, but he gets defensive and irritated because he sees that I have nothing to be threatened about. I know once I get to know her I'm sure it won't be that bad, but I still wonder if he's just going to start hitting the town with her all the time and having tons of fun. Help!

Mildly Green-Eyed

Jealousy is insecurity, yes -- but there's better security than dating people you don't really care about.

And if you've had two long-term relationships without really caring, and refer to being in love as " 'in love' kind of stuff" (I am imagining little quotation-mark hand gestures), it's easy for someone like me to get the impression that you're very, very uncomfortable with making yourself vulnerable.

It's okay. Common affliction.

But it's important to know this about yourself before you take on something as fraught as a girlfriend-turned-ex-turned-bestest-friend-turned-new-neighbor.

You'll need this knowledge to maintain your perspective, for one. Right as you are about jealousy in general, you do have cause for concern, since it's possible he will take some of your time or intimacy away and give it to her.

But you also need to realize that, given your inherent fear, you're bound to envision the worst; it's also possible you'll lose none of your boyfriend and even gain a new friend in this girl. Force your mind open to other-case scenarios, and use that to remain calm while you wait to see which one plays out -- and even take steps toward the best case by being friendly to her.

Knowing yourself can also keep your boyfriend off the defensive. Admit to him that it makes you jumpy to care about someone as much as you care about him, that it's a new feeling for you, and apologize for letting it get to you when you heard of his ex's return. Sharing this with him is honest, disarming and fair.

It's also the smart thing to do for yourself. If you lay your soul bare to him, and he is anything but gentle in handling it -- by continuing to get defensive and irritated on the subject of the ex, by not treating you with extra patience, by boxing you out of their friendship, by writing off even reasonable objections as jealousy, anything -- then you'll know he's not your guy.

Painful, painful, but in the end, always so useful to know.

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