Is (Will) the age gap between LO#1 and #2 be closer or between #2 and #3?

DS and DS#2 will be just over 2.5 years apart. I needed a break after pregnancy and breastfeeding and had a cp in between that time.

If we decide to jump on the three train after DS#2 is here, we'd like to start trying a year earlier! So looking at shooting for a 1.5 year gap!

(I want to be done having babies earlier and DH wants them as close together as possible with my comfort of spacing the pregnancies!)